PEM07-01

会場:302

時間:5 月 24 日 16:15-16:45

古気候復元における成層圏オゾンの影響: MRI-ESM による完新世中期実験
Impact of stratospheric ozone on paleoclimate reconstruction: Mid-Holocene experimentby using MRI Earth System Model
納多 哲史 1 ; 水田 亮 2 ; 出牛 真 2 ; 小寺 邦彦 3 ; 吉田 康平 2 ; 鬼頭 昭雄 4 ; 村上 茂教 5 ; 足立 恭将 2 ;余田 成男 1∗
NODA, Satoshi1 ; MIZUTA, Ryo2 ; DEUSHI, Makoto2 ; KODERA, Kunihiko3 ; YOSHIDA, Kohei2 ; KITOH, Akio4 ;MURAKAMI, Shigenori5 ; ADACHI, Yukimasa2 ; YODEN, Shigeo1∗
1

京都大学大学院 理学研究科, 2 気象研究所, 3 名古屋大学 太陽地球環境研究所, 4 筑波大学 生命環境系, 5 気象大学校
Graduate School of Science, Kyoto University, 2 Meteorological Research Institute, 3 Solar-Terrestrial Environment Laboratory,
Nagoya University, 4 Graduate School of Life and Environmental Sciences, University of Tsukuba, 5 Meteorological College
1

Numerical experiment of mid-Holocene (6000 years before present) is performed by using Meteorological Research Institute
Earth System Model (MRI-ESM) to investigate the impact of ozone distribution which is modulated by orbital elements on the
tropospheric climate. The result of interactive ozone calculation is compared to those of mid-Holocene and pre-industrial control
experiments in CMIP5/PMIP3, in which the ozone distribution was fixed to the value of 1850. Contribution of the chemical
processes shows anomaly up to +1.7 K in the Antarctic regions for the annual mean zonal mean temperature at 2 m from thesurface. This impact is caused by decrease in the area of sea ice, and the interrelationship in the trend is found to be opposite tothat of sea ice and the Antarctic ozone hole as observed in these decades.
Stratospheric warming in the Antractic spring due to the positive anomaly of ozone causes negative westerly anomaly of thepolar night jet by the thermal wind balance, and the annular mode response brings westerly anomaly near the surface. The
decrease of the surface westerly weakens the northward component of the Ekman transport in the ocean, suppresses the sea icetransport to lower latitudes, and produces the warming in the polar region.
The importance of chemical feedbacks is supported by a correction of cold bias of SST in the southern hemisphere which iscommonly seen in results of CMIP5/PMIP3 models. The comparison between the time variation of the sea ice distribution andthat of the stratosphere-troposphere coupling patterns show the importance of coupled chemistry process related to ozone in thereconstruction of mid-Holothese climate.
キーワード: オゾン, 太陽放射, 古気候, 地球システムモデル, 海氷
Keywords: ozone, solar radiation, paleoclimate, earth system model, sea ice

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PEM07-02

会場:302

時間:5 月 24 日 16:45-17:00

極域熱圏・電離圏の基本構造
Climatology of the polar thermosphere and ionosphere藤原 均 1∗ ; 三好 勉信 2 ; 陣 英克 3 ; 品川 裕之 3 ; 野澤 悟徳 4 ; 小川 泰信 5 ; 片岡 龍峰 5
FUJIWARA, Hitoshi1∗ ; MIYOSHI, Yasunobu2 ; JIN, Hidekatsu3 ; SHINAGAWA, Hiroyuki3 ;NOZAWA, Satonori4 ; OGAWA, Yasunobu5 ; KATAOKA, Ryuho51

成蹊大学 理工学部, 2 九州大学 大学院理学研究院, 3 情報通信研究機構, 4 名古屋大学 太陽地球環境研究所, 5 国立極地研究所
1Faculty of Science and Technology, Seikei University, 2 Department of Earth and Planetary Sciences, Faculty of Sciences,
Kyushu University, 3 National Institute of Information and Communications Technology, 4 Solar Terrestrial Environment Laboratory, Nagoya University, 5 National Institute of Polar Research

Recent observations from satellites and ground-based instruments have clarified various phenomena in the polar thermosphereand ionosphere, in particular, the cusp and polar cap region. The CHAMP satellite observations for a decade were the great success to understand the mass density variations in the global thermosphere. However, some basic features and/or climatology ofthe polar thermosphere and ionosphere seem to be still unknown. For example, amplitudes of the temperature and wind variations
during a solar cycle are not exactly known in the local area in and/or in the vicinity of the cusp/polar cap region. In addition,
contributions of the lower atmosphere to the temperature and wind variations in the thermosphere seem not to be understoodquantitatively in each local area. In order to understand climatology of the polar thermosphere and ionosphere, we have madesome observations with the EISCAT radar system and optical instruments in 2011-2015 and performed numerical simulations
with a whole atmosphere GCM. The five-year observations of the polar ionosphere with the EISCAT radar system show the large
difference between the ionospheres over Longyearbyen and Tromsoe; variations of the dayside ion temperature and ion motion
at Longyearbyen are larger than those at Tromsoe on average during geomagnetically quiet periods. The EISCAT data during theextremely low solar activity 2007-2008 have also clarified the basic state of the ionosphere which would be strongly affected by
the lower atmosphere. We will show the recent progress of our understandings of basic features of the polar thermosphere andionosphere from the observations and GCM simulations.
キーワード: 熱圏, 電離圏, 極域, EISCAT, GCM, シミュレーション
Keywords: thermosphere, ionosphere, polar region, EISCAT, GCM, simulation

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PEM07-03

会場:302

時間:5 月 24 日 17:00-17:15

GAIA を用いたスポラディック E 層出現特性の解析
Analysis of occurrence characteristics of sporadic E layers using GAIA
品川 裕之 1∗ ; 三好 勉信 2 ; 陣 英克 1 ; 藤原 均 3
SHINAGAWA, Hiroyuki1∗ ; MIYOSHI, Yasunobu2 ; JIN, Hidekatsu1 ; FUJIWARA, Hitoshi3
1
1

情報通信研究機構, 2 九州大学, 3 成蹊大学
NICT, 2 Kyushu University, 3 Seikei University

スポラディック E 層（Es）は、高度約 90km から 120km の間の領域に存在する非常に薄く高密度のイオン層である。
Es は、短波を利用した通信や放送に大きな影響を及ぼすことが知られており、宇宙天気予報においては重要な現象の一つである。Es は、基本的には下部熱圏、上部中間圏付近の中性風のシアと流星起源の金属イオンの組み合わせによってできると考えられているが、その形成や変動過程は定量的にはまだ十分に解明されていない。これまでの観測から、 Es
は季節変動、地方時変動、地理的な場所の依存性などを示すことが分かっている。中でも特徴的なのは、Es が北半球の夏には東アジアの中緯度付近で最も多く発生し、南半球の夏には南アメリカの中緯度付近で最も多く発生することである。この現象は観測的には古くから知られていたが、今日まで理論的に解明されていなかった。我々のグループでは、全大気圏と電離圏を矛盾なく結合し、下層大気に気象庁の再解析データを入力したモデル（GAIA: Ground-to-topside modelof Atmosphere and Ionosphere for Aeronomy）の開発を行ってきた。このモデルは、Es の構造を直接再現するにはまだ分
解能が十分とは言えないが、Es の発生条件を大まかに見積もることは可能である。今回は、GAIA のシミュレーション
データを用いて E 領域の中性風シアの解析を行った。その結果、風のシアは、これまでの観測で得られた Es の出現特性とほぼ同じく、北半球の夏には東アジアの中緯度付近で最も大きく、南半球の夏では南アメリカの中緯度付近で最も強くなることが分かった。本発表では、この中性風シア発生頻度の地域依存性のメカニズムについて議論する。
キーワード: スポラディック E 層, 大気圏, 電離圏, モデル, 中性風シア, 発生
Keywords: sporadic E layer, atmosphere, ionosphere, model, neutral wind shear, occurrence

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PEM07-04

会場:302

時間:5 月 24 日 17:15-17:30

Introduction of long-term whole atmosphere-ionosphere simulation database and future
updateIntroduction of long-term whole atmosphere-ionosphere simulation database and future
update
陣 英克 1∗ ; 三好 勉信 2 ; 藤原 均 3 ; 品川 裕之 1 ; Matsuo Tomoko4
JIN, Hidekatsu1∗ ; MIYOSHI, Yasunobu2 ; FUJIWARA, Hitoshi3 ; SHINAGAWA, Hiroyuki1 ; MATSUO, Tomoko4
1

情報通信研究機構, 2 九州大学, 3 成蹊大学, 4 米国大気海洋庁
National Institute of Information and Communications Technology, 2 Kyushu University, 3 Seikei University, 4 National Oceanicand Atmospheric Administration1

超高層大気領域は人工衛星や地上‐衛星間をつなぐ電波の通り道であり、その擾乱や変動は衛星の軌道や姿勢、また電波の伝搬に影響する。超高層大気の擾乱や変動の起源は、太陽フレアなど太陽面の活動が磁気圏を通して入ってくるだけではなく、地表付近の気象の影響も中層大気を通り入ってくることが知られてきた。我々は、電離圏・熱圏の全球分布を将来的に数値的に推測・予測するために、地表から熱圏上部までの中性大気領域と電離圏領域を相互に結合する
大気圏電離圏結合モデル（GAIA）を開発してきた。さらに、現実の太陽放射強度の変動として日々の F10.7 を入力する
以外に、モデルの下層大気領域に気象再解析データをナッジング手法により取り込み、現実の気象活動の影響による超高層大気変動を再現する試みを行ってきた。本発表では、1996 年から 2014 年まで行った気象再解析データを取り入れた大気圏電離圏シミュレーションのデータベースについて紹介する。データベースでは、太陽活動と自転に伴う変動のほかに、電離圏と熱圏の季節変動や、より周期の短い下層大気起源の周期的変動が見られている。また、下層大気の突発的な擾乱に伴う超高層大気の擾乱も再現されている（Jin et al, 2012; Liu et al., 2013, 2014）。本発表では、シミュレー
ションデータベースと観測との比較について報告する。また、今後モデルの精度向上に向けてデータ同化手法を取り入れようとしており、その試みについて紹介する。
キーワード: 宇宙天気, 電離圏, データ同化, データベース, 熱圏, シミュレーション
Keywords: space weather, ionosphere, data assimilation, database, thermosphere, simulation

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PEM07-05

会場:302

時間:5 月 24 日 17:30-17:45

Beacon experiment of the ionosphere in Japan and southeast Asia
Beacon experiment of the ionosphere in Japan and southeast Asia
山本 衛 1∗YAMAMOTO, Mamoru1∗
1
1

京都大学生存圏研究所
RISH, Kyoto University

We have been successfully conducted observations of total-electron content (TEC) of the ionosphere by the satellite-groundbeacon experiment. An unique dual-band (150/400MHz) digital receiver GRBR (GNU Radio Beacon Receiver) were developed
based on the recent digital signal processing technologies. The GRBR receivers were deployed first in Japan, and then in southeast
Asia, and other areas. Data from the GRBR network were used for the investigations of variety of ionospheric phenomena. We
have found mid-latitude summer nighttime anomaly (MSNA) over Japan, which is summer nighttime TEC enhancement at higher
latitudes. Longitudinal ”large-scale wave structures (LSWS)” in the low latitude were studied in detail as a source of equatorial
Spread-F (ESF) events. Also we were successful to measure the equatorial ionospheric anomaly (EIA) near 100E longitude inlarge latitudinal extent of at most +/-20 degrees around the geomagnetic equator. The technique is utilized for sounding rocketground experiment as well. We review the ionospheric studies with the GRBR network, and will discuss future direction of therelated studies.
キーワード: 衛星−地上ビーコン観測, 全電子数, 中低緯度電離圏, GRBR 観測網
Keywords: Satellite-ground beacon experiment, Total electron content, Middle- and low-latitude ionosphere, GRBR network

1/1

PEM07-06

会場:302

時間:5 月 24 日 17:45-18:00

Statistical analyses on the thermal plasma density of the plasmasphere from the Akebono
PWS observation
Statistical analyses on the thermal plasma density of the plasmasphere from the Akebono
PWS observation
長谷川 周平 1 ; 三好 由純 1∗ ; 北村 成寿 1 ; 桂華 邦裕 1 ; 小路 真史 1 ; 熊本 篤志 2 ; 町田 忍 1
HASEGAWA, Shuhei1 ; MIYOSHI, Yoshizumi1∗ ; KITAMURA, Naritoshi1 ; KEIKA, Kunihiro1 ;SHOJI, Masafumi1 ; KUMAMOTO, Atsushi2 ; MACHIDA, Shinobu1
1

名古屋大学太陽地球環境研究所, 2 東北大学大学院理学研究科地球物理学専攻
Solar-Terrestrial Environmment Laboratory, Nagoya University, 2 Department of Geophysics, Graduate School of Science, Tohoku University
1

The plasmasphere is a region of cold and dense plasma surrounding the Earth. The thermal plasma density of the plasmasphereis an important parameter for understanding the dynamics of the radiation belts as well as the inner magnetosphere, because thethermal plasma density controls the wave-dispersion relation, resonance conditions, etc. In this study, we conduct statistical analyses on the variations of the plasmasphere and plasmatrough, using electron density data derived from long-term plasma wave
observations by the PWS experiments on board the Akebono satellite. We investigate the solar cycle variations of the thermal
plasma density distribution. In deep plasmasphere, the thermal plasma density distributions along the field line do not significantly change during the solar cycle, and their distributions are well modeled as the diffusive equilibrium. On the other hand,
the thermal plasma density distributions drastically change during the solar cycle in the outer portion of the plasmasphere. The
thermal plasma density distributions are similar to the collisionless model during the solar active periods, while those are similar
to the diffusive equilibrium model during the solar quiet periods. We also investigate time variations of the plasmaspheric density
distribution during geomagnetic storms driven by CMEs and CIRs with superposed epoch analyses. The zero time corresponds
to the minimum of the Dst index. The plasmaspheric density shrinkage depends on the storm amplitudes. The recovery time of
the thermal plasma density is significantly different between CME- and CIR-storms. During the recovery phase of CIR-storms,
the plamapause does not recover quickly because of prolonged substorm activities during the high-speed steams. The recovery
rates of the thermal plasma density depend on the L-shell, which is consistent with the previous studies. We find that the recovery
rates of CME-storms are larger than that of CIR-storms.
Keywords: plasmasphere, electron density, akebono satellite, solar-cycle, geomagnetic storm

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PEM07-07

会場:302

時間:5 月 25 日 09:00-09:30

太陽活動領域：誕生から噴出まで
Solar Active Regions: From Birth to Eruption
鳥海 森 1∗TORIUMI, Shin1∗
1
1

国立天文台
National Astronomical Observatory of Japan

Solar-terrestrial environment is largely influenced by flares and CMEs sourced from the Sun. In particular, stronger events are
known to be produced from solar active regions (ARs) including sunspots. Therefore, it is of great importance to understandthe creation mechanism of ARs and their relationship with solar eruptions. Now it is widely accepted that ARs are caused byemerging magnetic flux, which is created by the dynamo effect in the convection zone. As a result of this flux emergence, several
magnetic elements of the same polarity merge together at the solar surface and eventually form a single sunspot. Observations
have revealed that large and complex ARs, the so-called delta sunspots, produce stronger flares. This may be because the freemagnetic energy (or non-potentiality) is stored in such complex, sheared ARs with larger magnetic flux. Recent developmentsin the numerical modeling of flux emergence and flare eruptions open the door to further understanding of physical mechanisms
behind such events. For example, our numerical simulations suggest that the flare-productive quadrupolar AR NOAA 11158,
which is responsible for many X- and M-class flares, is produced from a single flux tube that is greatly disturbed in the convection
zone during its emergence process. In this presentation, motivated by the above scientific curiosity, we review the observational
and theoretical progress in the field of flux emergence, AR formation including delta-sunspots, and the resultant triggering offlare eruptions. After that, we discuss the future prospects.
Keywords: the Sun, active region, flux emergence, flare, MHD

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PEM07-08

会場:302

時間:5 月 25 日 09:30-09:45

太陽フレアのトリガ過程に関する観測的研究
Observational Study of the Flare Trigger Process
伴場 由美 1∗ ; 草野 完也 1
BAMBA, Yumi1∗ ; KUSANO, Kanya111名古屋大学太陽地球環境研究所
STEL/Nagoya Univ.

Solar Flares are explosive phenomena driven by magnetic energy stored in the solar corona. Because interplanetary disturbances associated with solar flares sometimes impact terrestrial environments and infrastructure, understanding the flaretriggering mechanism is important not only from a solar physics perspective but also for space weather forecasting. There are
numerous observational studies and numerical simulations which attempted to reveal the onset mechanism of solar flares. However, because different observations support different models, the underlying mechanism of flare onset remains elusive, and thepredictability of flare occurrence is limited.
To elucidate flare-trigger mechanism, Bamba et al. 2013 investigated four major flare events that occurred in active regions
NOAA 10930 and NOAA 11158. We used data obtained by the Solar Optical Telescope (SOT) onboard the Hinode satellite.
We analyzed the spatio-temporal correlation between the detailed magnetic field structure and the emission image of the Ca II H
line at the central part of flaring regions for several hours prior to the onset of flares. We observed that characteristic magnetic
disturbances developed at the centers of flaring regions in the pre-flare phase. These magnetic disturbances can be classified into
two groups depending on the structure of their magnetic polarity inversion lines; to the so-called ”Opposite-Polarity (OP)” and”Reversed-Shear (RS)” magnetic field recently proposed by Kusano et al. 2012. The result strongly suggests that some major
flares are triggered by rather small magnetic disturbances. We also show that the critical size of the flare-trigger field varies
among flare events and briefly discuss how the flare-trigger process depends on the evolution of active regions.
Because of the limitation of SOT field of view, however, only four events in the Hinode data sets have been utilizable inour previous study. Therefore, increasing the number of events is required for evaluating the flare trigger model. Bamba et al.
2014 investigated the applicability of data obtained by the Solar Dynamics Observatory (SDO) to increase the data sample for astatistical analysis of the flare trigger process. SDO regularly observes the full disk of the sun and all flares although its spatial
resolution is lower than that of Hinode. We investigated the M6.6 flare which occurred on 13 February 2011 and compared theanalyzed data of SDO with the results of Bamba et al. 2013 using Hinode/SOT data. Filter and vector magnetograms obtainedby the Helioseismic and Magnetic Imager (HMI) and filtergrams from the Atmospheric Imaging Assembly (AIA) 1600Å were
employed. From the comparison of small-scale magnetic configurations and chromospheric emission prior to the flare onset,
we confirmed that the trigger region is detectable with the SDO data. We also measured the magnetic shear angles of the active
region and the azimuth and strength of the flare-trigger field. The results were consistent with Bamba et al. 2014. We concluded
that statistical studies of the flare trigger process are feasible with SDO as well as Hinode data.

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PEM07-09

会場:302

時間:5 月 25 日 09:45-10:00

2012 年 3 月 7 日 X5.4/X1.3 フレア: エネルギーの蓄積・トリガー・解放を探る
X5.4/X1.3 flares on 7 March 2012: Exploring the energy storage, trigger and release ofsolar flares
清水 敏文 1∗ ; 井上 諭 2
SHIMIZU, Toshifumi1∗ ; INOUE, Satoshi2
1
1

宇宙航空研究開発機構宇宙科学研究所, 2 名古屋大学太陽地球環境研究所
ISAS/JAXA, 2 STE laboratory, Nagoya University

太陽フレアは、磁力線の捻れとしてコロナに蓄積された自由エネルギーが突発的に解放され、場合によっては宇宙空間
へコロナプラズマの噴出を伴う。本講演では、2012 年 3 月に太陽面に存在した活動領域 11429 に注目する。2012 年 3 月
7 日には X5.4 および X1.3 フレアを起こし、これらのフレアは VarSITI/ISEST のスタディケースの一候補でもある。このフレアに伴うコロナ質量放出 (CME) は惑星間空間に伝播して、地球では 3 月 9 日に大きな磁気嵐を発生させている。この活動領域はδ型黒点を含み、領域全体が強くシアしている。理解に乏しいフレアのトリガー機構を学術的に理解する
ことは、宇宙天気のフレア発生予測にとって重要である。シアした磁場構造に対して、その磁気中性線上に小さなトリガ磁場が「反シア型」に成長することが、フレア発現の一つの磁場形態であると指摘されている。
「ひので」可視光磁場
望遠鏡 (SOT) の高精度磁場観測によって、X5.4 フレアに対する「反シア型」のトリガ磁場が磁気中性線上に特定されている。さらに、「ひので」の磁場および速度場観測から、1) トリガ磁場の横に、小さな双極の磁場が磁気中性線に沿って形成され、フレア発生の少なくとも 6 時間以上前から激しい音速ガス流がその磁場に沿って励起されていること、2) 激
しいガス流が徐々に双極の磁場を成長させ、その先に存在したトリガ磁場を徐々に押して、トリガ条件の磁場構造に向けて磁場配置を変化させていること、等を発見した。この観測結果は、光球ガスのダイナミクスがフレア発現のトリガに至らしめる上で重要な役割を果たしていることを示唆している。一方、その約１時間後に、同じ磁気中性線に沿った西側の領域で、X1.3 フレアが発生し、アーケード状の X 線構造が発達する。なぜ、一度に系全体の磁場が噴出せずに、２段階になったのだろうか？ X5.4 フレアに対して激しい光球ガスのダイナミクスが特定されたが、X1.3 フレアの発現には光球ガスのダイナミックスがどのように関わっているのだろうか？ 光球ベクトル磁場に基づいた NLFFF モデリン
グによってコロナ磁場の形状を推定し、ねじれ磁場の空間分布を導出した。各フレアの足下に現れるフレアリボン構造
から、エネルギー解放が起きた磁力線を時間的にトレースして、ねじれコロナ磁場のどの部分が噴出したのかを評価した。この活動領域の磁場特徴やダイナミックスを示して、フレア蓄積と発現について議論する。

キーワード: 太陽フレア, ひので, 光球磁場, コロナ, コロナ磁場, 宇宙天気
Keywords: Solar flare, Hinode, Photospheric magnetic field, corona, coronal field, space weather

1/1PEM07-10

会場:302

時間:5 月 25 日 10:00-10:15

4 重極磁場構造におけるホモロガスフレア
Homologous flare occurred at the quadrupole field
川畑 佑典 1∗ ; 清水 敏文 2
KAWABATA, Yusuke1∗ ; SHIMIZU, Toshifumi2
1
1

東京大学大学院理学系研究科地球惑星科学専攻, 2 宇宙航空研究開発機構宇宙科学研究所
Department of Earth and Planetary Science, The University of Tokyo, 2 Institute of Space and Astronautical Science, JAXA

Many models of the solar flare are suggested and they can explain some of the observed flares. However, they cannot explain
all of the observed flares. The purpose of our study is investigating such events. We focus on homologous flares, which occur
at the same location in the same active region repeatedly. We used Solar Optical Telescope (SOT) on board HINODE andAtmospheric Imaging Assembly (AIA) on board Solar Dynamics Observatory (SDO ). We can obtain three dimensional vectorof the magnetic field by using the spectropolarimetric data of SOT and investigate the coronal configurations by using the extreme
ultraviolet data of AIA. We analyze the active region NOAA 11967 which produced three M class flares on 2014 February 2.
These flares show homology and the magnetic field at the flaring region is quadrupole. There were four flare ribbons and they
showed rapid slipping motion. The photospheric flow can be seen between the sunspot and this flow may play a role in storing
free energy and triggering the flare.
キーワード: 太陽フレア, 磁気リコネクション
Keywords: solar flare, magnetic reconnection

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PEM07-11

会場:302

時間:5 月 25 日 10:15-10:30

Study on the Solar Flare Trigger Mechanism by using 3D Data Driven Magnetohydrodynamic Simulations
Study on the Solar Flare Trigger Mechanism by using 3D Data Driven Magnetohydrodynamic Simulations
MUHAMAD, Johan1∗ ; KUSANO, Kanya1 ; INOUE, Satoshi1
MUHAMAD, Johan1∗ ; KUSANO, Kanya1 ; INOUE, Satoshi1
1
1

STEL, Nagoya University
STEL, Nagoya University

Solar Flare can unleash large amount of energy from the Sun into the solar system and may affect global space based technologies on Earth. However, the detail process of the solar flare mechanism, especially in the early phase of the flare, is still notcompletely understood. It is believed that initially flare takes place from the highly sheared magnetic field in the active region of
the Sun which contains very large non-potential energy. This strong sheared field is then destabilized by some trigger processes
which responsible in releasing the free energy through some eruptions.
Several results from the previous numerical simulation study (Kusano et al., 2012) suggested that small magnetic flux which
is imposed to the various simple magnetic structures can trigger the eruptions. Two different types of small magnetic structuresnear the polarity inversion line (PIL) are suggested as the possible configurations for the trigger of flares. They are the smallbi-pole fields of opposite polarity or reversed shear compared to the highly sheared magnetic field in the scale of active region.
Started from this result, we extend this work by using more realistic configuration of magnetic fields which mimic the solar
coronal magnetic structure.
In this presentation, we will present some results of our simulations to elucidate the trigger process of solar eruption based on
the 3D magnetohydrodynamic (MHD) model. In order to do this, we perform Nonlinear Force Free Field (NLFFF) extrapolation(Inoue et al., 2014) using the vector magnetogram data of the active region NOAA 10930 from the Hinode satellite. The NLFFF
of the active region before the eruption showed that strong sheared magnetic field appeared near the PIL. We systematicallycarried out the numerical simulations, in which several emerging fluxes are injected onto different points in the NLFFF. As aresult, we confirmed that some types of small emerging flux can trigger the eruption. It verifies that the previous work mechanism(Kusano et al. 2012) can be applied to more realistic magnetic structure. Our result suggests that the position and intensity of theemerging flux with respect to the initial NLFFF condition is very crucial for triggering the solar eruption.
References:[1] Magnetic Field Structures Triggering Solar Flares and Coronal Mass Ejections,
K. Kusano, Y. Bamba, T. T. Yamamoto, Y. Iida, S. Toriumi, and A. Asai,
2012 ApJ 760 31 doi:10.1088/0004-637X/760/1/31[2] Nonlinear Force-Free Extrapolation of the Coronal Magnetic Field Based on the Magnetohydrodynamic Relaxation Method,
Inoue, S., Magara, T., Pandey, V. S., Shiota, D., Kusano, K., Choe, G. S., Kim, K. S.,
2014 ApJ 780 101 doi:10.1088/0004-637X/780/1/101

キーワード: Solar Flare, MHD Simulation, Nonlinear Force Free Field, Active Region
Keywords: Solar Flare, MHD Simulation, Nonlinear Force Free Field, Active Region

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PEM07-12

会場:302

時間:5 月 25 日 10:30-10:45

大振幅地磁気急始変化（SC）の性質
Properties of large amplitude geomagnetic sudden commencement (SC)荒木 徹 1∗ ; 新堀 淳樹 2
ARAKI, Tohru1∗ ; SHINBORI, Atsuki2
1
1

中国極地研究所, 2 京都大学生存圏研究所
Polar Research Institute of China, 2 Research Institute for Sustainable Humanosphere, Kyoto University

Araki[2014, EPS] は，1868 年以降の SC 振幅を調べ，1940 年 3 月 24 日の SC が最大であることを確かめた．この SCの振幅Δ H は，柿岡で 273nT 以上，Alibag で 310nT であった．Siscoe et al. [1968] の，SC 振幅Δ H と太陽風動圧 Pd の関係式，Δ H = αΔ (√ Pd）［α＝ f ｇ k，k；比例係数，ｆ；太陽風と磁気圏の相互作用に関わる係数（〜1-2），ｇ；地下誘導電流効果（〜1.5）］を使うと．対応する Pd 増加は 400-500nPa になる．これは 1868 年以降最大の惑星間空間衝撃波（IPS）に伴う Pd であるから，出来るだけ精密に決めたい（線形近似の妥当性の議論は別に必要である）．
磁気圏圧縮の際には，磁気圏界面電流 (MPC) の増加と共に沿磁力線電流 (FAC)・電離層電流（IC）が誘起されて SC 振
幅に LT 変化を生じさせ，それに応じて上記の比例係数ｋも LT 変化を示す [新堀，2014]．SC 振幅Δ H から対応する Pd
変化を求める際には，この LT 変化を考慮する必要がある．
通常 2nPa 程度の Pd が 30nPa を越すと磁気圏界面は静止軌道の内側に入って来る．その時の MPC, FAC, IC の地上磁場への寄与の割合が，Pd が小さい時に比べて異なり，SC 振幅 LT 変化も異なることが予想される．したがって，大振幅
SC の LT 変化を調べ，それを IPS-Pd の推定に反映させることに意味が出てくる．ここでは，振幅の LT 変化を中心に，大振幅 SC の性質を調べる．
柿岡や Alibag では，50nT 以上の SC の発生率は 5 ％以下，100nT 以上は１%以下になるので，統計的解析は出来ない．
多点同時観測のデータ解析を行う．

キーワード: 地磁気急始変化 (SC), 惑星間空間衝撃波, LT 変化, 大振幅
Keywords: geomagnetic sudden commencement(SC), interplanetary shock, LT variation, large amplitude

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PEM07-13

会場:302

時間:5 月 25 日 11:00-11:30

Progress in Understanding the Earth-affecting Coronal Mass Ejections
Progress in Understanding the Earth-affecting Coronal Mass Ejections
Gopalswamy Nat1∗GOPALSWAMY, Nat1∗1
1NASA Goddard Space Flight CenterNASA Goddard Space Flight Center

Coronal mass ejections (CMEs) producing solar energetic particle (SEP) events at Earth and causing geomagnetic storms are
obviously the Earth-affecting CMEs. The occurrence of SEP events depends on the outer structure of CMEs, viz. the MHD
shock, irrespective of the internal structure. On the other hand, geomagnetic storms occur when the internal magnetic structureof CMEs and/or the sheath behind the shock contain southward-pointing magnetic fields. The source locations of these two
types of CMEs are also different: SEP events require magnetic connectivity to Earth, whereas storm-producing CMEs need tobe directed toward Earth. Observations from the STEREO mission have contributed enormously to the study of Earth-affecting
CMEs because of the expanded field of view and viewing angles away from the Sun-Earth line. The increased field of viewcloser to the Sun helped us understand that shocks can form as close as about 1.25 solar radii from the Sun center. The onset oftype II radio bursts associated with CMEs has shown that shocks can form at large distances from the Sun (tens of solar radii).
SEPs are energized as soon as the shock forms and can continue until the shock arrival at Earth and even afterwards. Therefore,predicting SEP events is generally very difficult (there is little lead time). There is definitely 1-4 days of lead time in predicting
geomagnetic storms. There have been many attempts to predict the shock arrival using CME, Type II radio, and IPS observations.
The CME trajectory can be severely affected by nearby coronal holes, non-radial ejection, and preceding CMEs resulting in large
deviations in the predicted arrival times. We are far from predicting the orientation and strength of the CME magnetic field,
which is crucial in predicting the occurrence and strength of geomagnetic storms. Then there are problems like the extremely
mild space weather during solar cycle 24. Even though there are sufficiently large number of energetic CMEs ejected from theSun, they do not seem to produce very many high-energy SEP events and large geomagnetic storms. It appears that this strange
behavior can be attributed to a combination of weak solar activity and CME propagation in the altered heliosphere. This talksummarizes some of these issues related to Earth-affecting CMEs and how the issues will be tackled by the ISEST/MiniMax24
project of the SCOSTEP/VarSITI program.
キーワード: Coronal mass ejections, Solar Energetic Particle Events, Geomagnetic Storms, CME propagation, Solar Cycle,
SCOSTEP/VarSITI
Keywords: Coronal mass ejections, Solar Energetic Particle Events, Geomagnetic Storms, CME propagation, Solar Cycle,
SCOSTEP/VarSITI

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PEM07-14

会場:302

時間:5 月 25 日 11:30-11:45

GEMSIS-Sun: Numerical Modeling of Sun-Earth System on the Basis of Solar Observations (SUSANOO)GEMSIS-Sun: Numerical Modeling of Sun-Earth System on the Basis of Solar Observations (SUSANOO)
塩田 大幸 1∗ ; 片岡 龍峰 2 ; 三好 由純 1 ; 草野 完也 1 ; 山野内 雄哉 1
SHIOTA, Daikou1∗ ; KATAOKA, Ryuho2 ; MIYOSHI, Yoshizumi1 ; KUSANO, Kanya1 ; YAMANOUCHI, Yuya1
1
1

名古屋大学 太陽地球環境研究所, 2 国立極地研究所
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 National Institute of Polar Research

Solar wind including coronal mass ejections (CMEs) is a main driver of various space weather disturbances. MHD modelingof the solar wind is a powerful tool to understand the solar-terrestrial environment and to forecast space weather accurately.
Recently, we have developed an MHD model of the inner heliosphere on the basis of minimal input, namely, time series ofdaily synoptic observation of the photospheric magnetic field [Shiota et al. 2014]. The time series of MHD parameters at the
Earth position is passed to a radiation belt model [Miyoshi et al. 2004] for forecasting of the radiation belt energetic electron
flux. These programs are executed everyday on a server in STEL, Nagoya University and the results are uploaded on the website (http://st4a.stelab.nagoya-u.ac.jp/susanoo/). This system is named as Space-weather-forecast-Usable System Anchored by
Numerical Operations and Observations (SUSANOO). The calculated time profiles of solar wind velocity and magnetic field at
positions of planets agreed with in situ measurements around solar minimum (2007 -2009) [Shiota et al. 2014].
The MHD simulation of solar wind does not include CMEs and therefore this is a possible source of error of the forecast in
active period in solar cycle. We have been developing a CME model including magnetic flux ropes [Kataoka et al. 2009]. In themodel, each CME is injected as a twisted magnetic flux rope accompanying with a velocity pulse through the inner boundary of
the simulation and propagate into the solar winds. Thanks to the including flux ropes, the model is capable for a model of Dst index variation. We attempted to model the solar wind profile when multiple CMEs came from associated recent large-scale active
regions: NOAA 10486 in October to November 2003 (Halloween event). As a result, the strength of compressed magnetic field
becomes as high as about four times of background IMF when a fast CME interacts with the background solar wind. However,successive CMEs interact with each other to form much stronger magnetic filed due to compression of the magnetic cloud of thepreceding CME by shock associated the following CME.

キーワード: 太陽風, MHD, 放射線帯, 宇宙天気, コロナ質量放出
Keywords: solar wind, MHD, radiation belt, space weather, CME

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PEM07-15

会場:302

時間:5 月 25 日 11:45-12:00

太陽風予測モデル SUSANOO-SW の衛星観測との比較による定量的評価
Quantitative Evaluation of Solar Wind Prediction Model ”SUSANOO-SW” by Comparison with in-situ Measurements
山野内 雄哉 1∗ ; 塩田 大幸 1 ; 草野 完也 1
YAMANOUCHI, Yuya1∗ ; SHIOTA, Daikou1 ; KUSANO, Kanya111名古屋大学 太陽地球環境研究所
Solar-Terrestrial Environment Laboratory, Nagoya University

太陽風の擾乱は、宇宙天気において最も重要な要素の一つである。宇宙天気予報は、地球に到達する前にその擾乱を予測する試みである。現在、最も信頼できる予報では、地球前方に位置する ACE などの探査機の太陽風 in situ 観測が予報に利用されている。しかし、この方法のみでは ACE に到達する前の太陽風の情報は知り得ないため、ACE-地球間を太陽風が伝搬する 1 時間程度のリーディングタイムしか取ることができない。そこで、MHD シミュレーションを用いる
ことで、さらに未来の予測を行うことができる。
近年我々のグループでは、太陽表面磁場のリアルタイム観測データのみを入力として放射線帯の高エネルギー電子の変動を予測する宇宙天気予測モデル SUSANOO (Space-weather-forecast-Usable System Anchored by Numerical Operations
and Observations) を開発した。SUSANOO の太陽風モデル (SUSANOO-SW) [Shiota et al. (2014)] は、太陽表面磁場観測
データに磁場モデル・経験モデルを適用し、内部太陽圏の太陽風の三次元構造を再現する MHD シミュレーションである。SUSANOO-SW で再現した太陽極小期（2007〜2009 年）の太陽風の惑星の位置での時間変動は、磁場の相関係数が0.54〜0.73、速度の相関係数が 0.40〜0.58 と太陽風の in situ 観測をよく再現した [Shiota et al. (2014)]。これは、1 年単位の比較で評価を行ったため、グローバルな太陽風構造の再現性の良さが数字として現れたと理解できる。しかし、より短い時間スケールの詳細な比較を行うと、一部の再現結果が外れていることが確認される。不一致が起きる原因は、
SUSANOO-SW の内側境界条件を設定するモデルにあると考えられる。実際の予報に使うためには、さらに精度を高める必要がある。そこで本研究では、SUSANOO-SW モデルと in situ 観測とを詳細に比較し、再現性が悪くなる原因を究明した。
本研究ではまず、SUSANOO-SW モデルを用いて、太陽活動極小期から極大期まで（2007〜2014 年） の太陽風変動を計算した。以下の４つの基準で観測値との比較をし、モデルの精度を数値化した。
（１）Carrington Rotation(CR) ごとの速度変動の相関係数。
（２）速度・磁場変動の一致率：（２−ａ） 磁場の極性、（２−ｂ） 速度差がしきい値よりも小さいか、（２−ｃ） dv/dt の符号 。ここで、（２）は１時間ごとに判定を行い、一致する時間の割合を求めた。この結果、（１）については、 42.5%の CR で相関係数が 0.5 以上となり、（２）については、いずれも YES が NO を上回るとなった。この結果から、モデルと観測の不一致が現れるタイミングと内側境界条件設定過程との関係を考察し、
SUSANOO-SW の境界条件設定モデル改良案についても議論する。

キーワード: 太陽風, 宇宙天気, MHD
Keywords: solar wind, space weather, MHD

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PEM07-16

会場:302

時間:5 月 25 日 12:00-12:15

非円形フラックスロープの不安定性に関する数値解析研究
Numerical Analysis of Instability of M-shape Flux Rope in the Solar Corona
石黒 直行 1∗ ; 草野 完也 1
ISHIGURO, Naoyuki1∗ ; KUSANO, Kanya111名古屋大学 太陽地球環境研究所
Solar-Terrestrial Environment Laboratory, Nagoya University

The stability of magnetic flux rope in the solar corona is an important issue to understand the onset mechanism of solar
flares and the formation of coronal mass ejections (CMEs). The instability of axisymmetric flux rope, called torus instability, is
proposed to be the primary driver of solar eruption by Kliem and Toeroek (2006). They analyzed the ideal magnetohydrodynamic(MHD) stability of toroidal electric current channel for the mode of self-similar expansion, and concluded that the decay index
of environmental magnetic field determines the criterion of the instability. However, several observations suggested that flux
rope forms a non-axisymmetric loop in pre-eruptive state. In particular, the flux rope of M-shape structure, in which magnetic
field line is concave above a magnetic polarity inversion line, is thought to be related to the onset of solar eruption. For instance,
Moore et al. (2001) explained how the M-shape flux rope can be formed and erupts by tether-cutting reconnection. Recently,
Kusano et al. (2012) found that the pre-flare reconnection between the sheared arcade and the small-scale magnetic flux of typicalorientations favors the formation of M-shape flux rope and well triggers the tether-cutting reconnection scenario. However, thecritical condition for the instability of the M-shape flux rope is still unclear.
In this paper, we numerically study the stability and dynamics of the M-shape flux rope. We model the M-shape flux rope
using two current carrying tori which connect each other above the polarity inversion line and are anchored on the solar surface.
The equilibrium condition is derived from the force balance of the hoop force of tori and the Lorentz force acting from external
magnetic field. We also solve the equation of motion for the altitude of magnetic dip under the constraint that magnetic flux
across the flux rope is conserved. As a result, the M-shape flux rope can be destabilized if the intensity of electric current exceeds
the criterion and the altitude of magnetic dip ascends to the critical height. The numerical solution indicates that the decay index
at the critical height of magnetic dip is substantially lower than the criterion of axisymmetric torus instability. It suggests that theM-shape flux rope much easily erupt than the theoretical prediction of axisymmetric torus instability, and the filament eruption
may start even from a lower potion where the decay index is lower than the conventional criterion.
Keywords: Sun, instability, flare, CME

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PEM07-17

会場:302

時間:5 月 25 日 12:15-12:30

プロミネンスからコロナキャビティに渡って成り立つ温度-密度間の冪乗則
Power-law relation between temperature and density in a promince and a coronal cavity
金子 岳史 1∗ ; 横山 央明 1
KANEKO, Takafumi1∗ ; YOKOYAMA, Takaaki1
1
1

東京大学
The University of Tokyo

In this study, we discuss the formation mechanism of a solar prominence by the radiative condensation by using MHD simulations including optically thin radiative cooling and thermal conduction. Our main focus is on the relationship between thetemperature and density in a prominence and its coronal cavity.
Solar prominences are the cool dense plasma clouds in the hot tenuous corona. The formation model of prominences has notbeen established completely. The radiative condensation is believed to be a key process.
In the previous study, we proposed a model through the radiative condensation triggered by the formation of a flux rope: The
flux rope is formed by the reconnection after imposing converging and shearing motion on the footpoints of the coronal arcade
field. The radiative condensation is triggered by the thermal nonequilibrium inside the flux rope. We have demonstrated thismodel in our simulations and found an empirical scaling law between the temperature and the density of a prominence.
The remained issues in our previous study were that the prominence in our simulations had much higher temperature thanthat of the observed one, and that the physical meaning of the scaling law was unclear due to the unrealistic small contrast of
temperature and density between the prominence and the corona.
In this study, we allow the prominence temperature in our simulations to be lower, and reproduce more realistic prominences.
As a result, we successfully extend the previous empirical scaling law to a power law both in a prominence and its surrounding
coronal cavity. We also found that the power depends on the temperature gradient of each field line.
キーワード: 太陽プロミネンス, 太陽フィラメント
Keywords: solar prominence, solar filament

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PEM07-18

会場:302

時間:5 月 25 日 12:30-12:45

活動領域におけるコロナループ足下の遷移層で観測されるサブ秒角構造の特徴
Properties of sub-arcsecond transition-region structures at the footpoints of coronal loops
in the active-region plage
木村 泰久 1∗ ; 原 弘久 2
KIMURA, Yasuhisa1∗ ; HARA, Hirohisa2
1
1

東京大学大学院, 2 国立天文台
University of Tokyo, 2 National Astronomical Observatory of Japan

温度 5,800K の太陽光球上で起こるエネルギー解放が、外層の温度˜10,000K をもつ彩層と˜1MK をもつコロナを形成す
る原因と考えられている。コロナの構造であるコロナループの足下は光球上の反極性を持つ磁場につながっており、多くの X 線、極紫外線望遠鏡で観測されているように、1 秒角以上の幅を持つことが分かっている。ひので衛星の極紫外線分光装置、EIS で観測されたコロナループ足下のフィリングファクターとドップラー速度から、ループ内部にはさらに小
さい幅のループが存在することを示唆している。空間解像度 0.2 秒角を持つロケット観測望遠鏡 HiC の極紫外線撮像観
測が、幅 1 秒角以上のコロナループの内部に示唆されているような微細構造があることを証明した。コロナ加熱を理解するためには、サブ秒角のコロナの構造を観測することが重要であるが、５分間の HiC による観測以外に、要求される分解能のデータが無い。そこで我々は、サブ秒角の構造を詳しく調べるために Atomospheric Imaging Assembly(AIA) とInterface Region Imaging Spectrograph(IRIS) のデータを解析した。AIA のデータは空間分解能が 1.2 秒角、時間分解能が12 秒である一方で、IRIS はコロナと彩層の中間を空間分解能 0.3 秒角、時間分解能 10 秒で観測している。光球表面でkG の磁場を持つ活動領域プラージュの基底部において、彩層からコロナまでに急激に温度が上がる非常に厚さの薄い領域である遷移層にコロナループの微細構造が繋がっていると考え、遷移層を撮像観測している IRIS の Si IV の輝線を用いた。結果として、間欠的に明るくなり、半値幅で 0.5-1.0 秒角程度の直径を持つ構造がコロナループ基底部に普遍的に存在することが分かった。Si IV ラインの放射強度の変化が起こる位置は、コロナループ基底部の断面の範囲内で時間とともに動くことが明らかとなった。さらに、AIA で観測したコロナループ基底部の放射強度は、Si IV で観測されるサブ秒角の構造が出現した後、10-30 秒後に増光することが分かった。発表では、1 秒角より大きい幅を持つコロナループの内部でみられるサブ秒角の構造は何であるか、またその形成メカニズムについて考察したことを述べる。
キーワード: 太陽, コロナループ, 遷移層, IRIS
Keywords: sun, coronal loop, transition region, IRIS

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PEM07-19

会場:302

時間:5 月 25 日 14:15-14:30

初期太陽圏の物理状態について
On Physical condition in the early Heliosphere鈴木 建 1∗SUZUKI, Takeru1∗11名古屋大学 大学院理学研究科
School of Science, Nagoya University

初期太陽圏の物理状態の進化について発表する。原始惑星系円盤の進化を、乱流駆動型円盤風の役割に焦点を当てつつレビューした後、太陽風の進化についての我々の結果を紹介する。さらに、太陽圏の物理状態の変化が、周囲の太陽系惑星の形成や進化に与える影響についても議論する。
キーワード: 太陽風, 原始惑星系円盤, 磁気流体力学, 波動, 乱流
Keywords: Solar Wind, Protoplanetary Disk, Magnetohydrodynamics, wave, turbulence

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PEM07-20

会場:302

時間:5 月 25 日 14:30-14:45

非一様場でのアルフベン波の衝撃波形成
Shock formation of Alfven waves in a non-uniform medium
庄田 宗人 1∗ ; 横山 央明 1
SHODA, Munehito1∗ ; YOKOYAMA, Takaaki1
1
1

東京大学大学院理学系研究科地球惑星科学専攻
Department of Earth and Planetary Science, University of Tokyo

Alfven waves, generated by photospheric granule motion, are considered to play a significant role in the energetics of coronalheating and solar wind acceleration. In many theoretical Alfven wave models, coronal high temperature is supported by continuous energy supply by Alfven waves and the ponderomotive force due to the local dissipation of Alfven waves is responsible
for solar wind acceleration. In linear theory dissipation due to viscosity and diffusivity is the only way to take out wave energy,
which is too inefficient for coronal heating. Therefore some nonlinear processes such as phase mixing, shock formation andturbulent heating are the promising mechanisms for coronal heating and solar wind accelerations.
In this study we concentrate on shock heating among some nonlinear processes. The aim of our research is to estimate theshock formation time of Alfven waves in a non-uniform medium. In case of uniform media, shock formation time is estimatedanalytically, while in non-uniform case it is not yet investigated sufficiently. We perform one-dimensional magnetohydrodynamic simulations for the estimation of shock formation time. A rightward-going Alfvenic wave packet of single wavelength is
set initially and we calculate its nonlinear propagation. Background magnetic field is assumed to be uniform and only the density
is set to be non-uniform in our simulation. The shock formation time is obtained by Fourier spectrum evolution. Due to the
non-uniformity of the background, nonlinearity of Alfven waves decreases as they propagate, which leads to the retardation andprevention of shock formation. We compare our numerical results with weakly nonlinear analytical results and show its validity.
Analytical results, expressed by Lambert’s W function, indicates that in the corona Alfven waves hardly steepen, whereas in theinterplanetary space the background condition is favorable for shock formation.

キーワード: アルフベン波, コロナ加熱, 太陽風
Keywords: Alfven wave, coronal heating, solar wind

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PEM07-21

会場:302

時間:5 月 25 日 14:45-15:00

太陽彩層中における非線形アルフベン波の伝播および反射
Propagation and reflection of nonlinear Alfven wave in the solar chromosphere河野 隼也 1∗ ; 横山 央明 1
KONO, Shunya1∗ ; YOKOYAMA, Takaaki1
1
1

東京大学
The University of Tokyo

It has been suggested that Alfvén waves, generated in the photosphere and propagating along the magnetic flux tube, cancarry enough energy to the low-plasma-beta region in the upper chromosphere and the dissipation of waves is one of the possible
mechanisms to heat the solar chromosphere. Temperature of the chromosphere is low and the plasma gas is partially ionized. The
collisions between plasmas and neutrals cause additional diffusion of the magnetic fields, which is called ambipolar diffusion.
On the other hand, the compressible waves are generated by the nonlinear effect of the magnetic pressure associated with the
Alfvén waves propagating upwards from the photosphere, and form shock waves in the chromosphere. In previous studies, it
has been indicated that the dissipation of generated shock waves can give enough thermal energy to heat the chromosphere. The
effect of the magnetic diffusion to the nonlinear propagation of Alfvén waves in the chromosphere has not been investigatedenough. Some observations show the reflection of Alfvén waves at the top boundary of the chromosphere, which is called thetransition region. It is important to discuss the dissipation mechanisms of waves in consideration of the reflection mechanism at
the top and bottom boundaries of the chromosphere.
In this study, we investigate the reflection of Alfvén waves propagating along a vertically open magnetic flux tube in thechromosphere at the transition region and photosphere. If we assume the atmospheric condition in the solar quiet region, thedamping length of waves which have frequencies of 1–100 mHz by the magnetic diffusion is estimated to become much larger
than the thickness of the chromosphere. For investigating the dissipation of Alfvén waves in the chromosphere, we should
consider the condition where the reflection at the photosphere and transition region efficiently occurs and more Alfvén waves
are trapped in the chromosphere. We investigate the propagations of the nonlinear Alfvén waves by performing one-dimensional
numerical simulations. As a result, 60–70 % of the incident Alfvénic pulse waves with frequencies of 10–100 mHz are reflected
at the transition region. Most of reflected waves from the transition region penetrate into the convection zone without beingreflected at the bottom of the photosphere. We perform simulations in different magnetic field structures and confirm that theresults are almost the same in any cases. It is considered to be important to take the energy flux going from the top and bottom
boundaries of the chromosphere into account for the dissipation of Alfvén waves in the chromosphere. In the case where theinitial velocity amplitude of Alfvén wave is set to be 1.0 km s−1 , the compressible waves generated by the nonlinear effect may
have enough energy to heat the chromosphere. If the initial velocity amplitude is set to be smaller, less compressible waves are
generated and other dissipation mechanisms of the Alfvén waves may become effective.
キーワード: 彩層加熱, アルフベン波, 磁気拡散, 非線形
Keywords: chromospheric heating, Alfven wave, magnetic diffusion, nonlinear

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PEM07-22

会場:302

時間:5 月 25 日 15:00-15:15

白色光増光現象を引き起こす太陽フレアの特徴
Characteristics that enhance white-light emission in solar flares
渡邉 恭子 1∗ ; 増田 智 2 ; 北川 潤 2
WATANABE, Kyoko1∗ ; MASUDA, Satoshi2 ; KITAGAWA, Jun2
1

宇宙航空研究開発機構宇宙科学研究所, 2 名古屋大学太陽地球環境研究所
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2 Solar-Terrestrial Environment Laboratory,
Nagoya University
1

In association with large (such as X-class) solar flares, we sometimes observe enhancements of visible continuum radiation,
which is known as a white-light flare . Because many white-light events show a close correlation between the time profiles andlocations of white-light emission, and the hard X-rays and/or radio emission, it is believed that the origin of white-light emission
is non-thermal electrons. However, not all large solar flares have white-light enhancements, and non-thermal electrons exist evenin micro-flares. There should be some necessary condition to generate white-light enhancements.
To understand what conditions generate a white-light flare, we analyzed 42 M- and X-class flares observed with Hinode/SOT
during the period from January 2011 to August 2013. Comparing the white-light (19 events) and no white-light (23 events)
events, we concluded that the key factor needed to generate white-light enhancement is the precipitation of large amounts ofnonthermal electrons into a compact region within a short time duration (Kitagawa et al., submitted to ApJ).
In this paper, we present the statistical results until December 2014. Not only the Hinode/SOT white-light (G-band (4305A)
and continuum (Blue: 4505A, Green: 5550A, Red: 6684A)) data, but we also check SDO/HMI continuum data. The total
number of events is now about twice that of Kitagawa s study. We compared the white-light emission data with GOES, hard
X-ray emission data and/or the strength of the photospheric magnetic fields and looked for any relationship between them.
キーワード: 太陽フレア, 白色光, 粒子加速
Keywords: solar flare, white-light, particle acceleration

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PEM07-23

会場:302

時間:5 月 25 日 15:15-15:30

電波観測における白色光太陽フレアの特徴
Characteristics in solar white-light flares based on radio observations
増田 智 1∗ ; 北川 潤 1 ; 渡邉 恭子 2
MASUDA, Satoshi1∗ ; KITAGAWA, Jun1 ; WATANABE, Kyoko2
1

名古屋大学太陽地球環境研究所, 2 宇宙航空研究開発機構宇宙科学研究所
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Institute of Space and Astronautical Science, Japan Aerospace
Exploration Agency

1White-light flare is a solar flare in which an enhancement in white-light continuum is detected. Although most of white-lightflares are large flares in energy like GOES X-class flare, it is not correct that only the amount of released energy determine
if a solar flare becomes a white-light flare. To understand what generates a white-light flare, we analyzed 42 M- and X-classflares observed with Hinode/SOT during the period from January 2011 to August 2013. Among these 42 events, the numberof white-light flares was 19. Comparing the white-light and no white-light events, we concluded that the key factor to generate
white-light enhancement is the precipitation of large amount of nonthermal electrons within a short time duration into a compact
region (Kitagawa et al., submitted to ApJ).
In this paper, we analyzed the 10 events (white-light: 4 events, no white-light: 6 events) among the 42 events, which wereobserved with Nobeyama Radio Heliograph (NoRH) and Nobeyama Radio Polarimeters (NoRP). GHz microwave are emitted bygyrosynchrotron from very-high energy (˜MeV) accelerated electrons. The peak intensity in 17 and 35 GHz does not show any
significant difference between the white-light and no white-light events. This indicates that such high-energy electrons does notcontribute white-light enhancement. The spectrum of gyrosynchrotron emission usually has a peak frequency which corresponds
to the turning point (turn-over frequency) between the optical thick part in the lower frequency range and the optically thin partin higher frequency range. The white-light flares show systematically high turn-over frequency than that of the no white-light
events. The higher turn-over frequency might correspond to stronger magnetic field. This is consistent that white-light flares
tend to be compact. As for the time evolution of the spectrum, the no white-light flares tend to show the spectral hardening. This
indicates that the magnetic mirror effectively works in no white-light flares because of the weak magnetic field in the flare loop.
Keywords: solar flare, particle acceleration

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PEM07-24

会場:302

時間:5 月 25 日 15:30-15:45

太陽彩層における微小構造に関する二次元数値シミュレーション
Two-dimensional simulation of the small scale structure in the solar chromosphere飯島 陽久 1∗ ; 横山 央明 1
IIJIMA, Haruhisa1∗ ; YOKOYAMA, Takaaki1
1
1

東京大学理学系研究科地球惑星科学専攻
Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo

Recent observation revealed the highly dynamic and fine structures in the solar chromosphere. The solar chromosphere is
known to have wide range of the plasma beta, high nonlinearity with shock waves, cooling from the radiation, thermal conduction
by the non-thermal electron, and weak ionization rate. All of the processes above have opportunity contributing to the dynamics
of the solar chromosphere. In order to get the proper interpretation of the observation in the solar chromosphere, the numericalsimulation with the various effects can be very useful tool. In our study, a new radiative magnetohydrodynamic code is developed
for the dynamical simulation of the solar chromosphere. The numerical domain includes the upper part of the convection zone tothe lower part of the corona. The convective motion as a driver of the dynamics in the upper atmosphere is consistently modeledusing the radiative transfer calculation and the realistic equation of state. The thermal conduction from the non-thermal electronis also included. In this talk, we will report the numerical implementation from this numerical code and the first results filledwith small scale structures in the two-dimensional domain.
Keywords: solar chromosphere, wave, convection, magnetohydrodynamics

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PEM07-25

会場:302

時間:5 月 25 日 15:45-16:00

野辺山 45m 電波望遠鏡によるミリ波の太陽彩層観測と宇宙天気
Millimetric observation of the solar chromosphere and space weather using the Nobeyama
45m radio telescope
岩井 一正 1∗ ; 下条 圭美 1
IWAI, Kazumasa1∗ ; SHIMOJO, Masumi1
1
1

国立天文台野辺山太陽電波観測所
Nobeyama Solar Radio Observatory, National Astronomical Observatory

太陽彩層の大気構造は太陽大気の過熱機構や太陽面で発生する諸現象を理解するため基礎情報であり、宇宙天気の基礎研究として重要である。太陽からのミリ波の放射は、主に彩層からの熱制動放射である。この放射は局所熱力学平衡状態で形成され、Rayleigh-Jeans の法則が適用される波長である。また熱制動放射の光学的厚さは電子密度と温度で決まる。よってミリ波帯域を多波長で観測することで、輝度温度から放射領域の温度や密度といった大気構造を推定することが可能である。しかし、ミリ波・サブミリ波の大型望遠鏡の多くは太陽のような高い輝度の天体を観測することを想定して設計されていない。そのため、この波長帯での太陽の高空間分解観測は極めて稀である。本研究では、野辺山 45m
電波望遠鏡を用いて、85 と 115GHz において黒点暗部を分解可能な空間分解可能の単面鏡観測を初めて行った。本研究では電波吸収体 (ソーラーフィルター) を用いることで、受信機の飽和を回避した。観測の結果、ミリ波の輝度温度分布
は活動領域・静穏領域の両方で紫外連続光 (1700 Å) と極めて高い相関があることが分かった。黒点暗部の輝度温度の上限値は静穏領域と同程度であった。一方でプラージュ領域は静穏領域よりも高い輝度温度であった。45m 電波望遠鏡のビームには、幅の広いサイドローブが存在する。加えて、黒点暗部はプラージュ領域に囲まれている。よって実際の黒
点暗部の輝度温度は観測値より低いと考えられる。これはミリ波では黒点暗部は静穏領域より高い輝度温度であると予想する多くの彩層大気モデルと矛盾する。この結果は、実際の大気では、遷移層の高度が既存の大気モデルよりも低い
可能性があることを示唆している。

キーワード: 太陽, 電波, ミリ波, 彩層, 宇宙天気
Keywords: Sun, Radio radiation, millimeter, Chromosphere, space weather

1/1PEM07-26

会場:302

時間:5 月 25 日 16:15-16:45

脈動オーロラ時に見られる広いエネルギー帯の電子散乱と中層大気への影響についてWide energy electron precipitation associated with the pulsating aurora and its impact on
the middle atmosphere
三好 由純 1∗ ; 大山 伸一郎 1 ; 齊藤 慎司 1 ; 栗田 怜 1 ; 藤原 均 2 ; 片岡 龍峰 3 ; 海老原 祐輔 4 ;Kletzing Craig5 ; Reeves Geoff6 ; Santolik Ondrej7 ; Clilverd Mark8 ; Rodger Craig9 ; Turunen Esa10 ;土屋 史紀 11MIYOSHI, Yoshizumi1∗ ; OYAMA, Shin-ichiro1 ; SAITO, Shinji1 ; KURITA, Satoshi1 ; FUJIWARA, Hitoshi2 ;KATAOKA, Ryuho3 ; EBIHARA, Yusuke4 ; KLETZING, Craig5 ; REEVES, Geoff6 ; SANTOLIK, Ondrej7 ;CLILVERD, Mark8 ; RODGER, Craig9 ; TURUNEN, Esa10 ; TSUCHIYA, Fuminori11
1

名古屋大学太陽地球環境研究所, 2 成蹊大学, 3 国立極地研究所, 4 京都大学生存圏研究所, 5 アイオワ大学, 6 ロスアラモス
国立研究所, 7 Charles University in Prague, Czech Rep., 8 British Antarctic Survey, UK, 9 University of Otago, NZ, 10 Sodankyla
Geophysical Observatory, University of Oulu, Finland, 11 東北大学大学院理学研究科惑星プラズマ・大気研究センター
1
Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Seikei University, 3 National Institute of Polar Research, 4 RISH,
Kyoto University, 5 University of Iowa, USA, 6 Los Alamos National Laboratory, USA, 7 Charles University in Prague, Czech
Rep., 8 British Antarctic Survey, UK, 9 University of Otago, NZ, 10 Sodankyla Geophysical Observatory, University of Oulu, Finland, 11 PPARC, Tohoku University

The pulsating aurora is caused by intermittent precipitations of tens keV electrons. It is also expected that not only tens keVelectrons but also sub-relativistic/relativistic electrons precipitate simultaneously into the ionosphere owing to whistler-mode
wave-particle interactions. We analyzed the pulsating aurora event in November 2012 using several ground-based observation
data; EISCAT, riometer, and sub-ionospheric radio waves, and the Van Allen Probes satellite data. The electron density profile
obtained fromthe EISCAT Tromsoe VHF radar identifies the electron density enhancement at >68 km altitudes. The electron energy spectrum derived from an inversion method indicates the wide energy electron precipitations from 10 keV - 200 keV. The riometerand network of sub-ionospheric radio wave observations also showed the energetic electron precipitations during this period.
During this period, the footprint of the Van Allen Probe-A satellite was very close to Tromso and the satellite observed rising
tone emissions of the lower-band chorus (LBC) waves near the equatorial plane. Using the satellite observed LBC and trappedelectrons as an initial condition, we conducted a computer simulation of the wave-particle interactions. The simulation showed
simultaneous precipitation of electrons at both tens of keV and a few hundred keV, which is consistent with the energy spectrum
estimated by the inversion method using the EISCAT observations. This result revealed that electrons with a wide energy range
simultaneously precipitate into the ionosphere in association with the pulsating aurora. We also discuss the possible impacts on
the middle atmosphere due to precipitations of wide energy electrons during the pulsating aurora.
キーワード: 電子降り込み, ジオスペース, 中層大気
Keywords: energetic electron precipiation, Geospace, middle atmosphere

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PEM07-27

会場:302

時間:5 月 25 日 16:45-17:00

太陽プロトンイベントでの航空機放射線被ばく
Radiation dose of aircrews during solar proton events
片岡 龍峰 1∗ ; 佐藤 達彦 2
KATAOKA, Ryuho1∗ ; SATO, Tatsuhiko2
1
1

国立極地研究所, 2 日本原子力研究開発機構
National Institute of Polar Research, 2 Japan Atomic Energy Agency

A significant enhancement of radiation doses is expected for aircrews during ground-level enhancement (GLE) events, while
the possible radiation hazard remains an open question during non-GLE solar energetic particle (SEP) events. Using a new
air-shower simulation driven by the proton flux data obtained from GOES satellites, we show the possibility of significant
enhancement of the effective dose rate of up to 4.5 uSv/h at a conventional flight altitude of 12 km during the largest SEP eventthat did not cause a GLE. As a result, a new GOES-driven model is proposed to give an estimate of the contribution from theisotropic component of the radiation dose in the stratosphere during non-GLE SEP events. We show further development of ourradiation dose model with some applications, including the most recent GLE 72 occurred on 16 Jan 2014.
キーワード: 太陽プロトンイベント, 放射線被ばく
Keywords: solar proton events, radiation dose

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PEM07-28

会場:302

時間:5 月 25 日 17:00-17:15

太陽高エネルギー粒子による中層大気中での微量化学種の変動：オゾンと硝酸
Variation of trace chemical species induced by solar energetic particles in the middle
atmosphere: ozone and nitric acid中井 陽一 1∗ ; 望月 優子 1 ; 丸山 真美 1 ; 秋吉 英治 2 ; 今村 隆史 2
NAKAI, Yoichi1∗ ; MOTIZUKI, Yuko1 ; MARUYAMA, Manami1 ; AKIYOSHI, Hideharu2 ; IMAMURA, Takashi2
1
1

理研仁科加速器研究センター, 2 国立環境研究所
RIKEN Nishina Center, 2 National Institute for Environmental Studies

Influences on the terrestrial environment of super solar flares have attracted interests recently. In a super solar flare, a large
amount of protons, X-rays, gamma-rays etc. emitted from the surface of the sun intrude into the terrestrial atmosphere, which iscalled a solar energetic particle (SEP) event. In particular, high-energy protons come down to the stratosphere. The SEP protons
can induce dissociation of nitrogen molecules. A part of dissociated nitrogen atoms contribute to increase of odd nitrogen oxides(NOx) and reactive odd nitrogen spices (NOy). Consequently, the SEPs influence the ozone concentration through the chemical
reactions in the atmosphere.
We have performed simulations for variation of chemical composition in SEP events by solving a large number of rate equations
for concentrations of chemical spices without taking into account of transport processes, i.e., simple Box-model simulations.
More than 70 chemical spices including ions and about 480 chemical reactions are adopted in the present simulation. A large
number of ionic processes including recombination in the stratosphere were treated for the first time to our knowledge.
We assume that the energy deposits from the SEP protons to the chemical species determine the yields of prompt products. As
a result, we can consider the prompt products to be generated from nitrogen and oxygen molecules of major components of theair. The estimation of the energy deposit is carried out using the calculations of ion-pair creation by the SEP protons [1]. For
the yield estimation of the prompt products, the G-values are used [2,3], where the G-values are given by amount of products
per absorbed energy of 100eV. During a SEP event, we deal with both the photochemical reactions and the reactions induced by
the SEP protons in the simulation. Variation of chemical composition in a SEP event is estimated as a difference between the
result of the simulation including the processes triggered by the SEP protons and that by taking account of only photochemical
reactions.
In this talk, we will mainly report the results by our Box-model simulation for the variations of ozone and nitric acid for the
SEP event observed in October-November 2003.
References[1] C.H. Jackman et al., Atmos. Chem. Phys. 8, 765 (2008).
[2] C. Willis and A. W. Boyd, Int. J. Radiat. Phys. Chem. 8, 71 (1976).
[3] H. Mätzing, Adv. Chem. Phys. LXXX, 315 (1991).

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PEM07-29

会場:302

時間:5 月 25 日 17:15-17:30

サイクル 23/24 における銀河宇宙線の太陽変調現象
The solar modulation of galactic cosmic rays during the cycle 23/24
三宅 晶子 1∗ ; 柳田 昭平 2
MIYAKE, Shoko1∗ ; YANAGITA, Shohei2
11

茨城工業高等専門学校, 2 茨城大学理学部
National Institute of Technology, Ibaraki College, 2 Ibaraki University, Faculty of Science

太陽圏内に進入したエネルギー数十 GeV 以下の銀河宇宙線は、太陽風や惑星間空間磁場による強度変動、すなわち太陽変調現象を生じる。宇宙線の強度は惑星間空間磁場の強度や極性、磁極の傾き、また太陽風速度の変化に合わせて変化するため、数値計算により銀河宇宙線太陽変調を再現・予測する場合にはこれらの変化を考慮に入れた計算が必要になる。
本発表では、サイクル 23/24 における銀河宇宙線の太陽変調現象の数値計算結果を報告し、極小期が予想される次期サイクルでの銀河宇宙線太陽変調の予測を議論する。

キーワード: 銀河宇宙線, 太陽変調, 太陽圏, 惑星間空間磁場
Keywords: galactic cosmic ray, solar modulation, heliosphere, Interplanetary magnetic field

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PEM07-30

会場:302

時間:5 月 25 日 17:30-17:45

マウンダー極小期の宇宙線強度変動
Variation of the intensity of galactic cosmic rays during the Maunder Minimum
宮原 ひろ子 1∗ ; 堀内 一穂 2 ; 門叶 冬樹 3 ; 加藤 和浩 3 ; 森谷 透 3 ; 横山 祐典 4 ; 松崎 浩之 4 ;本山 秀明 5 ; 片岡 龍峰 5
MIYAHARA, Hiroko1∗ ; HORIUCHI, Kazuho2 ; TOKANAI, Fuyuki3 ; KATO, Kazuhiro3 ; MORIYA, Toru3 ;YOKOYAMA, Yusuke4 ; MATSUZAKI, Hiroyuki4 ; MOTOYAMA, Hideaki5 ; KATAOKA, Ryuho5
1
1

武蔵野美術大学, 2 弘前大学, 3 山形大学, 4 東京大学, 5 国立極地研究所
Musashino Art Univ., 2 Hirosaki Univ., 3 Yamagata Univ., 4 The Univ. of Tokyo, 5 NIPR

Variations of the galactic cosmic-ray flux during the Maunder Minimum (AD1645-1715) are examined based on carbon-14 intree rings and beryllium-10 in ice cores. Variations of beryllium-10 content in ice cores have suggested that the flux of galactic
cosmic rays have increased by ˜40 percent for about one year around every other solar cycle minima, when solar dipole magnetic
field was negative. Periodicity of the events is ˜26-28 years, corresponding to the Hale cycle during the Maunder Minimum.
These extreme enhancements of cosmic rays are suggested to be possibly caused by a change in the large scale structure ofheliospheric magnetic field, associated with extremely weakened solar activity. To obtain more reliable ages for those events, wehave been also measuring the carbon-14 content in tree rings dated by dendro-chronology.
キーワード: マウンダー極小期, 宇宙線, 太陽活動, 太陽圏, 宇宙気候, 宇宙線生成核種
Keywords: Maunder Minimum, cosmic rays, solar activity, heliosphere, space climate, cosmogenic nuclide

1/1

PEM07-31

会場:302

時間:5 月 25 日 17:45-18:00

Open Data of Sunspot and aurora records in the Chinese chronicles : 7th to 13th century
Open Data of Sunspot and aurora records in the Chinese chronicles : 7th to 13th century
早川 尚志 2 ; 玉澤 春史 1∗ ; 河村 聡人 1 ; 磯部 洋明 3
HAYAKAWA, Hisashi2 ; TAMAZAWA, Harufumi1∗ ; KAWAMURA, Akito D.1 ; ISOBE, Hiroaki3
1

京都大学大学院理学研究科附属天文台, 2 京都大学大学院総合生存学館, 3 京都大学宇宙総合学研究ユニット
Kwasan and Hida Observatries, Graduate School of Science, Kyoto University, 2 Graduate School of Advanced Integrated
Studies in Human Survivability, Kyoto University, 3 Kyoto University Unit of Synergetic Studies for Space

1

Records of sunspots and aurora observations in pre-telescopic historical documents can provide useful information about solar
activity in the past. This is also true for extreme space weather events, as they may have been recorded as large sunspots observedby the naked eye or as low-latitude auroras. In this study, we present the results of a comprehensive survey of sunspots and aurora
records in Chinese formal chronicles spanning the 7th to 13th . This chronicles contain records of continuous observations withwell-formatted reports conducted as a policy of the government. A brief comparison of the frequency of sunspots and aurora
observations and the observations of radioisotopes as an indicator of the solar activity during corresponding periods is provided.
In our project, we survey and compile the sunspots and aurora records in historical documents from various locations andlanguages, ultimately providing it to the academic community, not only community of natural science but also human and social
sciences, as open data.
Keywords: sunspot, aurora, archaeoastronomy, extream space weather

1/1PEM07-32

会場:302

時間:5 月 26 日 09:00-09:15

巨大黒点 12192 はなぜコロナ質量放出を起こさなかったのか？
Why big sunspot 12192 did not produce CME ?
柴田 一成 1∗ ; 石井 貴子 1 ; 河村 聡人 1
SHIBATA, Kazunari1∗ ; ISHII, Takako1 ; KAWAMURA, Akito1
1
1

京都大学理学研究科附属天文台
Kwasan and Hida Observatories, Kyoto University

2014 年 10 月下旬に出現した黒点 12192 の面積は A ＝ 2750 MSH = Millionth Solar
Hemisphere に達した。これは 1990 年 11 月の巨大黒点 6368（面積 A ＝ 3080 MSH）以来の24 年ぶりの巨大黒点であり、大フレアや大磁気嵐を起こす可能性があるとして、世界的な注目を集めた。実際、東のリムに見え始めた 10 月 17 日から西のリムに消えた 10 月 30 日までの 2 週間の間に、X クラスフレアを 6 回引き起こした。これは今サイクルにおいて、一活動領域当たりの X クラスフレアの数では最多であった。ところが、一見不思議なことに、これらの 6 回の X クラスフレアは、一つもコロナ質量放出（CME) を引き起こさず、その結果、太陽風はきわめて静かであり、磁気嵐は全く発生しなかった。
京大飛騨天文台では、この巨大黒点 12192 を SMART 望遠鏡とドームレス太陽望遠鏡を用いて、詳細に観測し、6 回のうちの２回の X クラスフレアの観測に成功した（10 月 19 日 UT ５時３分（ピーク時）X1.1, 10 月 24 日 UT21 時 40 分
（ピーク時）X3.1）。
本講演では、飛騨天文台における上記の黒点とフレアの観測の概要を紹介するとともに、なぜこの巨大黒点の X クラ
スフレアは CME を引き起こさなかったか、過去の CME フレアと比較することにより統計的な観点から考察する。得られた結論を一言でまとめると、「同じ X 線強度のフレアに対しては、黒点が巨大になればなるほど、
CME は発生しにくくなる」というものである。
キーワード: フレア, コロナ質量放出, 黒点, 磁場, 電磁流体力学, 宇宙天気予報Keywords: flare, CME, sunspot, magnetic field, magnetohydrodynamics, space weather prediction

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時間:5 月 26 日 09:15-09:30

ひので衛星と SDO 衛星から迫る太陽表面における磁場輸送
Investigation of surface magnetic flux transport by use of Hinode/SOT and SDO/HMI
飯田 佑輔 1∗ ; 堀田 英之 2
IIDA, Yusuke1∗ ; HOTTA, Hideyuki2
1
1

JAXA, 2 HAOJapan Aerospace Exploration Agency, 2 High Altitude Observatory

Since magnetic field on the solar surface triggers various solar activities, it is very important to understand their structure interms of the space weather. An important issue is transport mechanism of magnetic flux. It is thought that the flow dominates
the magnetic field on the solar surface. Although the transport is treated as a pure diffusion process for long time, recent solar
observations suggest the differences from the diffusion.
We reported the relationship between the travel distance of the magnetic flux concentration and the elapsed time from thebirth of the concentrations. The sub-diffusion scaling was found in the time range longer than 2x104 seconds for the firsttime. The investigation is, however, limited because the analysis is done by using the magnetogram obtained by Solar Optical
Telescope onboard the Hinode satellite (Hinode/SOT), which does NOT cover the whole Sun. Thus in this study we investigate
the relationship with the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory (SDO/HMI), which covers
the whole Sun. Since the spatial resolution of SDO/HMI is lower than that of Hinode/SOT, we use both telescopes in order to
see the influence of the resolution on the analysis. We find the similar sub-diffusion scaling with the power law index of 0.7 ±0.1. SDO/HMI shows a slightly larger magnitude. This difference may come from the difference of spatial resolution between
the telescopes. In the presentation, we also plan to show the 3D MHD simulation of the magneto-convection if time permits.
キーワード: 太陽, 対流, 磁場, 拡散
Keywords: Sun, convection, magnetic field, diffusion

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時間:5 月 26 日 09:30-09:45

太陽活動サイクルのフェーズと大きな宇宙天気イベントの発生について
Solar cycle phase and occurrence of intense space weather events
亘 慎一 1∗ ; 渡邉 堯 1
WATARI, Shinichi1∗ ; WATANABE, Takashi1
1
1

情報通信研究機構
National Institute of Information and Communications Technology

黒点数であらわされる太陽活動サイクルの長さや形はサイクル毎に変化する。大きな宇宙天気イベントの太陽活動のフェーズに対する依存性を議論するためには、各太陽活動サイクルについて規格化をする必要がある。例えば、大きな
宇宙天気イベントが、太陽活動サイクルで一様に起こるかどうか調べることは重要なことである。ここでは、太陽活動
サイクルの長さ、立ち上がり時間、立下り時間を使って太陽活動サイクルの形の規格化を行った。大きな太陽フレアの発生、強い地磁気嵐の発生などについての解析結果について報告する。
キーワード: 太陽活動サイクル, 宇宙天気, 極端現象
Keywords: solar cycle, space weather, extreme event

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時間:5 月 26 日 09:45-10:00

宇宙天気事象時に電離圏地面電流回路で発達する電場・電流Electric field and currents in the ionosphere-ground circuit during space weather disturbances
菊池 崇 1∗ ; 橋本 久美子 2 ; 海老原 祐輔 3 ; 冨澤 一郎 4 ; 亘 慎一 5
KIKUCHI, Takashi1∗ ; HASHIMOTO, Kumiko2 ; EBIHARA, Yusuke3 ; TOMIZAWA, Ichiro4 ; WATARI, Shinichi51

名古屋大学太陽地球環境研究所, 2 吉備国際大学, 3 京都大学生存圏研究所, 4 電気通信大学宇宙電磁環境研究センター, 5
情報通信研究機構
1
Nagoya University/Solar-Terrestrial Environment Laboratory, 2 Kibi International University, 3 Kyoto University, Research Institute for Sustainable Humanosphere, 4 Center for Space Science and Radio Engineering, Univ. of Electro-Communications,5
National Institute of Information and Communications Technology

When the CME or CIR hit the magnetosphere, the electric field and currents are generated by the dynamos in the magnetosphere and transmitted to the polar ionosphere down the magnetic field lines and further to the low latitude ionosphere.
The transmitted electric field drives the Hall currents that close with themselves in the high-midlatitude ionosphere and thefield-aligned currents close with the Pedersen currents that extend to the equatorial ionosphere near-instantaneously, where thePedersen currents are intensified considerably by the Cowling effect appearing as the equatorial electrojet (EEJ). Thus, the geomagnetic disturbances often appear concurrently at high latitudes and the dayside equator with magnitude decreasing withlatitude but amplified at the equator. At midlatitudes, the electric fields transmitted from high latitude are detected with the HF
Doppler sounder, which are well correlated with the EEJ. The concurrent development of the midlatitude electric field and EEJ iscommonly observed during the storm sudden commencements (SC), geomagnetic PC and Pi pulsations, quasi-periodic DP2 andstorm/substorm convection and overshielding events. As shown in this paper, disturbances in the GIC (geomagnetically induced
currents) on the ground are also well correlated with the EEJ and electric field in the ionosphere. The observations suggest thatthe electric current flows from the dynamo in the magnetosphere into the ground via the ionosphere. The ionospheric currents
and GIC are connected by the displacement currents flowing on the wave front of the TM0 (TEM) mode waves propagating in
the Earth-ionosphere waveguide (ionosphere-ground transmission line) [Kikuchi, 2014], where the Poynting flux is transported
in the neutral atmosphere between the ionosphere and ground.

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時間:5 月 26 日 10:00-10:15

2014 年 12 月の連発 CME に対する極冠域電離圏の応答: 2 台の全天イメージャによる 5 日間連続モニタリング
Responses of polar cap ionosphere to successive CMEs in Dec 2014: 5 days continuous
monitoring with two all-sky imagers
細川 敬祐 1∗ ; 田口 聡 2 ; 塩川 和夫 3 ; 小川 泰信 4 ; 大塚 雄一 3
HOSOKAWA, Keisuke1∗ ; TAGUCHI, Satoshi2 ; SHIOKAWA, Kazuo3 ; OGAWA, Yasunobu4 ; OTSUKA, Yuichi3
1

電気通信大学, 2 京都大学大学院理学研究科, 3 名古屋大学太陽地球環境研究所, 4 国立極地研究所
University of Electro-Communications, 2 Graduate School of Science, Kyoto University, 3 Solar-Terrestrial Environment Laboratory, Nagoya University, 4 National Institute of Polar Research
1

In December 2014, three coronal mass ejections (CMEs) occurred successively during 4 days
interval from December 18 to 21. These CMEs arrived at the Earth respectively at December 21, 22
and 23 and caused a small magnetic storm (Dst ˜-50 nT). During this interval, two all-sky airglow
imagers were operative in Longyearbyen, Norway (78.1N, 15.5E) and Resolute Bay, Canada (74.7N, 265.1E)
and monitoring the polar cap ionosphere continuously for 5 days from December 20 to 24. The two
all-sky imagers observed continuous generation/propagation of polar cap patches from the dayside
towards the nightside across the polar cap region during a prolonged interval of southward IMF Bz.
Such a continuous transportation of high-density plasma is visualized for the first time. At thetime of the arrival of second CME, the IMF Bz was directed strongly northward. During this period,
the polar cap shrank significantly, which implies that the magnetosphere was almost closed during
such a strongly northward IMF condition. By using the 5 days continuous optical data in the polar
cap region, we will discuss various responses of polar cap ionosphere to CME-induced solar wind
disturbances.
キーワード: 極冠域, 極冠パッチ, 極冠オーロラ, コロナ質量放出
Keywords: Polar cap, Polar cap patches, Polar cap aurora, Coronal Mass Ejection (CME)

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PEM07-37

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時間:5 月 26 日 10:15-10:30

宇宙線による新粒子生成促進についての重イオンビームでの検証実験
Laboratory experiment with heavy ion beam for verification of new particle formation bycosmic rays
鈴木 麻未 1∗ ; 増田 公明 1 ; 伊藤 好孝 1 ; さこ 隆志 1 ; 松見 豊 1 ; 中山 智喜 1 ; 上田 紗也子 1 ;三浦 和彦 2 ; 草野 完也 1
SUZUKI, Asami1∗ ; MASUDA, Kimiaki1 ; ITOW, Yoshitaka1 ; SAKO, Takashi1 ; MATSUMI, Yutaka1 ;NAKAYAMA, Tomoki1 ; UEDA, Sayako1 ; MIURA, Kazuhiko2 ; KUSANO, Kanya111名古屋大学太陽地球環境研究所, 2 東京理科大学
Solar-Terrestrial Environment Laboratory,Nagoya University, 2 Tokyo university of science

It is considered that the solar activity may affect the global climate, but the correlation mechanism is still not understood.
One of the possible mechanisms for the correlation is the cloud formation by the galactic cosmic rays, which are modulatedby the variation of solar magnetic activity. This relation was clearly indicated by the good correlation observed for the galactic
cosmic-ray intensity and the global low-cloud amount. This hypothesis includes the ion-induced nucleation model, in which newparticles in the atmosphere are created efficiently through atmospheric ions produced by cosmic rays, and finally these particles
grow up to the size of cloud condensation nuclei. In this study, a laboratory experiment for verification of the hypothesis has
been conducted with a reaction chamber. A flow of clean air with water vapor, ozone and sulfuric dioxide was introduced to ametallic chamber, where we irradiated UV light for solar irradiance and beta rays or accelerator beam for cosmic rays. The beamof the heavy ion accelerator HIMAC at National Institute of Radiological Sciences was used in the present experiment.
The result so far showed that ion density in the chamber increased due to the heavy ion irradiation and enhancement of thenumber of aerosol particles due to its was confirmed. In this presentation, I will report the results of the heavy ion irradiation
experiments. Heavy ion beam of nitrogen and xenon was used because their ionization loss is different by a factor of 60.
The ionization loss could be an index representing the ability to ionize the air molecules that is, parameters that contribute toatmospheric ion generation. Since it is considered that the aerosol particle generation would be increased according to the amountof ions, the experiment was carried out for these ions. The results showed that produced ion density was not different for bothions with different ionization power, and aerosol particle production efficiency was almost the same. The less ionization density
for Xe ions might be due to large recombination of produced ions along the ion beam tracks.

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時間:5 月 26 日 10:30-10:45

星雲遭遇による白亜紀末の寒冷化と大量絶滅
Global cooling and mass extinction driven by a dark cloud encounter
二村 徳宏 1∗ ; 戎崎 俊一 2 ; 丸山 茂徳 3
NIMURA, Tokuhiro1∗ ; EBISUZAKI, Toshikazu2 ; MARUYAMA, Shigenori3
1
1

岡山天文博物館, 2 理化学研究所, 3 東京工業大学 地球生命研究所
Okayama Astronomical Museum, 2 RIKEN, 3 Earth-Life Science Institute, Tokyo Institute of Technology

We found a broad positive anomaly in iridium across over ∼5 m in a pelagic deep sea sediment core sample, in addition to a
spike in iridium at the K-Pg boundary related to the Chicxulub asteroid impact. Any mixtures of materials on the surface of the
Earth cannot explain the broad iridium component. On the other hand, we found that an encounter of the solar system with agiant molecular cloud can explain the component, if the molecular cloud has a size of ∼100 pc and the central density of ∼2000
protons/cc.
Kataoka et al . (2013; 2014) pointed that the encounter with a dark cloud may drive an environmental catastrophe to lead amass extinction. The solid particles from the dark cloud accreted onto the Earth and stayed for several months or years in thestratosphere: Since their sunshield effect is as large as -9.3 W m−2 , it can be a cause of a global climate cooling in the last 8 Myrof Cretaceous period, which is suggested by the variations of stable isotope ratios in oxygen (Barrera & Savin, 1999; Li & Keller,
1999; 1998; Barrera & Huber, 1990) and strontium (Barrera & Savin, 1999; Ingram, 1995; Sugarman et al ., 1995). The resultant
extensions of the continental ice sheet cause a regression of the sea level, too. The global cooling seems to be associated with thedecrease in the diversity of fossils, which eventually lead to the mass extinction at the K-Pg boundary.
The mass extinction at K-Pg boundary is widely thought to be caused by an impact of an asteroid (Alvarez et al ., 1980;
Schulte et al ., 2010) at 65.5 Ma. However, a complete extinction of the total family by just one asteroid impact seems rather
difficult because of the following two reasons. (1) A severe environment turn-over would finish few years after impact, thesolid particles and sulphate launched by the asteroid impact is settled down for only few months (troposphere) to few years(stratosphere) and negative radiative forcing become negligible after a few years from the impact. (2) There were similar impacts
without environmental catastrophe on the Earth, for example, Woodleigh, Chesapeak and Popigai craters. However, there are noevidences of association for mass extinction. It is difficult to explain why only Chicxlub impact leads mass extinction but theother three comparable impacts did not.
It is worth noting that the encounter with the dark cloud can perturb the orbit of asteroids and comets by its gravitational
potential may cause asteroid impact or comet shower. The asteroid impact at K-Pg, therefore, may be one of the consequencesof the dark cloud encounter.
We conclude that the cause of the climate cooling at the End-Cretaceous was driven by an encounter with a giant molecular
cloud, with such an encounter and related perturbation in global climate a more plausible explanation for the mass extinction
than a single impact event, Chicxulub.
キーワード: 星雲の冬, 星雲遭遇, 宇宙気候学, 白亜紀末, K-Pg 境界, 大量絶滅
Keywords: Nebula Winter, dark cloud encounter, Space Climate, End-Cretaceous, K-Pg boundary, mass extinction

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時間:5 月 26 日 11:00-11:15

時系列予測機 UFCORIN を利用した GOES X 線ライトカーブにおける太陽フレア予報研究
Prediction Study of Solar Flare Events in GOES X-ray Flux using Time-Series Prediction
Engine UFCORIN
村主 崇行 1∗ ; 柴山 拓也 2 ; 羽田 裕子 3 ; 磯部 洋明 4 ; 根本 茂 5 ; 駒﨑 健二 5 ; 柴田 一成 3
MURANUSHI, Takayuki1∗ ; SHIBAYAMA, Takuya2 ; HADA MURANUSHI, Yuko3 ; ISOBE, Hiroaki4 ;NEMOTO, Shigeru5 ; KOMAZAKI, Kenji5 ; SHIBATA, Kazunari3
1

理化学研究所計算科学研究機構, 2 名古屋大学太陽地球環境研究所, 3 京都大学大学院附属天文台, 4 宇宙総合学研究ユ
ニット, 5 株式会社ブロードバンドタワー
1
RIKEN Advanced Institute for Computational Science, 2 Solar-Terrestrial Environment Laboratory, Nagoya University, 3 Kwasanand Hida Observatories, Kyoto University, 4 Unit of Synergetic Studies for Space, 5 BroadBand Tower, Inc.

We have been developing UFCORIN, an automated space weather prediction system based on machine-learning technologies.
Our aim is twofold: one is to provide real-time space weather forecast that thoroughly utilize the huge amount of solar observation data available today. The other is to discover the observational flare-triggering features, by analyzing the big data with theclear goal of predicting the solar flares.
UFCORIN stands for Universal Forecast Constructor by Optimized Regression of INputs. As the name suggests, UFCORIN
is designed as a generic time-series predictor, which can be set to predict arbitrary time series from arbitrary numbers and kindsof input time series.
Using our system we predict maximum of GOES X-ray flux for 24-hour period in the future. As inputs to the predictor, we use
wavelet powers of the full disk line-of-sight magnetogram obtained by the Helioseismic and Magnetic Imager (HMI) on board
the Solar Dynamic Observatory (SDO). We also use the total magnetic flux data by SDO/HMI, and past data of GOES X-ray flux
as inputs. The simulated prediction ran for 2 years (2011-2012) with 1-hour time resolution. To predict X, ≥M and ≥C classflares events, we first predict the real value of the GOES X-ray flux maximum, and then apply different thresholds for different
events. These thresholds are part of the prediction parameter subject to optimization.
Following Bloomfield et al. [2012], we use true skill statistics (TSS) to compare the performance of various prediction strategies. Our best TSS values using HMI and GOES data are 0.692, 0.470 and 0.566, respectively, for predicting X, ≥M and ≥Cclass flares. These TSS values are comparable to previous studies such as those by Song et al. [2009], by Bloomfield et al.
[2012], and by Bobra & Couvidat [2014]. We emphasize that we predict flares for the 2-years continuous period, and make no
use of active region detection. In contrast, all of the previous studies are based on active region images and selected set of events.
At the annual meeting, we would also like to report the progress of our ongoing research, for example the search of flarefeatures in SDO/AIA ultraviolet images. Also, our techniques can be applied to the prediction of space weather events other thansolar flares, such as solar wind, solar energetic particles, and geomagnetic disturbances. We are also trying to quantify the socialand economic impacts of the solar flares, in order to provide customized space weather forecast for various human activities.
キーワード: 太陽フレア, 宇宙天気, フレア予測, SDO, ビッグデータ, 機械学習
Keywords: Solar flares, Space weather, Flare prediction, SDO, Big data, Machine learning

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時間:5 月 26 日 11:15-11:30

ニューラルネットワークを用いた太陽風入力による東京上空 foF2 の擾乱予測
Prediction of foF2 variation above Tokyo using solar wind input to a neural network
内田 ヘルベルト陽仁 1∗ ; 三宅 亙 2 ; 中村 真帆 3
UCHIDA, Herbert Akihito1∗ ; MIYAKE, Wataru2 ; NAKAMURA, Maho3
1
1

東海大学大学院工学研究科, 2 東海大学工学部, 3 東京学芸大学
Graduate School of Engineering, Tokai University, 2 Tokai University, 3 Tokyo Gakugei University

Neural network has the ability to learn the empirical relation from input data. It is often used to produce empirical prediction
models of several space environmental parameters. One operational model (Nakamura, 2008) used K-index input to predict
foF2 variations and ionosphere storms above Tokyo. There are also several works for predicting geomagnetic indices such as
Dst from the solar wind inputs (e.g., Watanabe et al., 2002). These studies lead us to expect that the prediction of foF2 at the
disturbed situation can be more accurate when solar wind parameters are used to the inputs. Recently the availability of solar
wind parameters from the Advanced Composition Explorer became longer enough to overlap one solar activity. In this study,
solar wind proton velocity and IMF-By, IMF-Bz are used to the input to predict the foF2 disturbances above Tokyo. The K-index
input model (Nakamura, 2008) was also recreated using the same data term as the SW input model. The SW input model tends
to predict more often the negative disturbance cases, and it predicted daytime quick variations more accurate than the K-index
input model. Statistical comparison of the predicting ability of those 2 models will be discussed, and the contribution of the solar
wind input parameters to the foF2 will be tested using an artificial input.
Keywords: ionosphere, foF2, prediction, neural network, solar wind

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PEM07-41

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時間:5 月 26 日 11:30-11:45

Prediction of MeV electron flux throughout the outer radiation belt by multivariate autoregressive model
Prediction of MeV electron flux throughout the outer radiation belt by multivariate autoregressive model
坂口 歌織 1∗ ; 長妻 努 1 ; Spence Harlan2 ; Reeves Geoffrey3
SAKAGUCHI, Kaori1∗ ; NAGATSUMA, Tsutomu1 ; SPENCE, Harlan2 ; REEVES, Geoffrey3
1

情報通信研究機構, 2 University of New Hampshire, 3 Los Alamos National Laboratory
National Institute of Information and Communications Technology, 2 University of New Hampshire, 3 Los Alamos National
Laboratory
1

The radiation belts are consisted of relativistic energy electrons in MeV range. The electron flux in the outer belt is highly variable depending on both solar wind and magnetospheric conditions. Enhanced fluxes sometimes cause deep dielectric charging
on spacecraft and therefore satellite anomaly happens after the discharge. Prediction of such MeV electron variations is needed
for safety operation of the satellite in the near Earth’s orbit, but the physical processes of acceleration, loss, and transport of relativistic electrons are not fully understood so far. Japanese space weather information center at NICT has developed a multivariate
autoregressive (AR) model for the prediction of electron flux at geostationary orbit (GEO). The model can estimates future flux
variations by a few days lagging response of solar wind parameter changes [Sakaguchi et al., 2013]. Now, we have developed
new models to predict electron flux variation throughout the outer radiation belt at L=3?6. Observation data of 2.3 MeV electronsin 2012-2014 by Van Allen Probes are used as predictor time series variate. The appropriate combinations of explanation variate
are examined and selected respectively for each of L value (∆L=0.2) model among geomagnetic indices (AE, Kp, Dst) as well
as solar wind parameters (speed, BZ, BS, Pdyn). The combinations of these variates systematically change according to L-value
shift. In the presentation, we show the estimation method of multivariate AR coefficient matrixes and discuss about estimatedcombinations of explanation variate. Also we show past prediction results that were validated by observation data based on two
skill scores of prediction efficiency and persistence.
キーワード: radiation belt, prediction, Van Alen Probes
Keywords: radiation belt, prediction, Van Allen Probes

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時間:5 月 26 日 11:45-12:00

ひまわり 8 号に搭載された宇宙環境モニター（SEDA）による初期観測
Initial Observations of Space Environment Data Acquisition Monitor (SEDA) on Board
Himawari-8
長妻 努 1∗ ; 坂口 歌織 1 ; 久保 勇樹 1
NAGATSUMA, Tsutomu1∗ ; SAKAGUCHI, Kaori1 ; KUBO, Yuki1
1
1

情報通信研究機構
National Institute of Information and Communications Technology

New Japanese meteorological satellite, Himawari-8, was successfully launched on October 7, 2014. Space environment dataacquisition monitor (SEDA) is on board Himawari-8, as one of the housekeeping information for satellite operation. SEDA
consists two sensors. One is proton sensor, which has 8 separate diode detectors. The energy range of the proton detectors arefrom 21.6 MeV to 81.4 MeV.
The other is electron sensor, which measures internal charging currents caused by energetic electrons. There are eight sensor
plates arranged in a stack and each plate responds to a different energy range. As a result, energetic electrons whose energy range
between 0.2 to 4.5 MeV can be measured by the electron sensors. The time resolution of each sensors is 10 sec. The field ofview of SEDA is eastward. Thus, the specification of SEDA is suitable for monitoring the energetic electrons and protons above
Japanese meridian of Geostationary orbit.
Himawari-8/SEDA has been operating since November 3, 2014. Based on the agreement between Japanese Meteorological
Agency (JMA) and NICT, JMA is providing Himawari/SEDA data in near-real time since January 21. 2015. Currently we arechecking the quality of Himawari-8/SEDA data. Results of initial observation by Himawari-8/SEDA will be introduced in ourpresentation.
キーワード: 宇宙天気予報, ジオスペース, 放射線帯, プロトン現象, 高エネルギー粒子, 静止軌道
Keywords: Space Weather Forecast, Geospace, Radiation Belts, Proton Event, High Energy Particles, Geostationary Orbit

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PEM07-43

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時間:5 月 26 日 12:00-12:15

地表気温および気候テレコネクションパターンに対する太陽風の影響
Influence of solar wind on surface temperatures and climate teleconnection patterns
伊藤 公紀 1∗
ITOH, Kiminori1∗
1
1

横浜国立大学環境情報研究院
Yokohama National University

太陽風の気候影響を探るため、相関係数を地図化した相関地図を用い、太陽風強度の指標である地磁気擾乱指数 (aa 指数) と、地表気温および気候テレコネクションパターンとの関係を求めた。QBO (赤道域成層圏準二年振動) による層化を行い、可能な場合は太陽黒点数も考慮した。対象とした期間は、QBO 位相 (西風、東風) データの信頼性が高い 1942
年から 2014 年とした。相関の時間窓は最短 10 年、最長 73 年である。
図 1 に、1 月の aa 指数と 2 月の地表気温との相関地図の例を示す。時間窓は 1942 年〜2014 年で、QBO の位相と黒点
数 (大、中、小) で層化した。各条件により、異なる相関地図が得られている。北極振動や太平洋十年規模振動などのテレコネクションパターンと地表気温の相関地図と類似している場合も見られる。
このような検討の結果、太陽風の気候影響はテレコネクションパターンの気候影響と同程度であることが分かった。
太陽風と北極振動の関係は良く知られているが、他のテレコクションパターンとの相関も強い。直接あるいは間接に、太陽風が各テレコネクションパターンを励起していると考えられる。

キーワード: 太陽風, aa 指数, テレコネクションパターン, 地表気温, QBO
Keywords: solar wind, aa index, teleconnection pattern, surface temperature, QBO

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PEM07-P01

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

ミニ太陽極大期における磁気嵐
Magnetic storms during solar ’mini-max’
海老原 祐輔 1∗ ; 田中 高史 2 ; フォック メイチン 3
EBIHARA, Yusuke1∗ ; TANAKA, Takashi2 ; FOK, Mei-ching31
1

京都大学生存圏研究所, 2 九州大学, 3 NASA GSFC
RISH, Kyoto University, 2 Kyushu University, 3 NASA GSFC

Large magnetic storms, such as Dst being less than -100 nT, have rarely been observed during Solar Cycle 24. One of thereasons would be a weak driver in the solar wind. We focus on another possibility; the influence of the solar EUV radiation on thestorm intensity. According to the ring current simulation coupled with the ionosphere, the intensity of the ring current becomeshigh when the background ionospheric conductivity is high. The reason is that the shielding electric field is weak and ions withenergy of the order of keV penetrate deep into the inner magnetosphere when the ionospheric conductivity is high. According to
the magnetohydrodynamics (MHD) simulation coupled with the ionosphere, the convection electric potential is weak when the
background ionospheric conductivity is high. Thus, the ring current is expected to be weak because the keV ions are primarilytransported from the near-earth plasma sheet by the convection electric field. This is opposite to that expected from the ring
current simulation. We evaluate and discuss the overall influence of the solar radiation on the intensity of the ring current.
Keywords: Magnetic storms, Ring current, Solar Max, Solar radiation, Ionospheric conductivity

1/1

PEM07-P02

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

次世代 M-I 結合シミュレーションを用いたバスティーユイベントの磁気圏応答
Global MHD simulation of the magnetospheric response of the Bastille day storm
久保田 康文 1∗ ; 長妻 努 1 ; 田 光江 1 ; 田中 高史 2 ; 藤田 茂 3
KUBOTA, Yasubumi1∗ ; NAGATSUMA, Tsutomu1 ; DEN, Mitsue1 ; TANAKA, Takashi2 ; FUJITA, Shigeru3
11

情報通信研究機構, 2 九大・宙空センター, 3 気象大学校
NICT, 2 SERC, Kyushu University, 3 Meteorological College

We are developing a real-time numerical simulator for the solar wind-space-magnetosphere-ionosphere coupling system using
next a generation magnetosphere-ionosphere coupling global MHD simulation. The feature of simulation has an advanced
robustness to strong solar wind case because a triangular grid is used, which is able to calculate in the uniform accuracy over thewhole region. The resolution is 7682 grids in the horizontal direction and 240 grids in the radial direction. The inner boundary of
the simulation box is set at 2.6 Re. We want to investigate the reproduction of the magnetosphere-ionosphere simulation result in
the case of strong solar wind. Therefore we compared the simulation results with the observation of the Bastille day storm event(2000/6/15), in which the solar wind velocity was above 1000 km/s and the value of Bz reached -60 nT. In this lecture, we willreport the result compared with AE index, CPCP, and artificial satellites observation.
キーワード: グローバル磁気流体シミュレーション, 磁気圏, 極端現象
Keywords: global MHD simulation, magnetosphere, extreme event

1/1

PEM07-P03

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

極微小惑星間空間磁場（1nT 未満）のもとでの電離圏対流強化
Ionospheric convection enhancement for extremely weak (<1 nT) interplanetary magnetic field
岩木 美延 1∗ ; 片岡 龍峰 2 ; 渡辺 正和 3 ; 藤田 茂 4 ; 田中 高史 3 ; 行松 彰 2 ; 細川 敬祐 5 ;Grocott Adrian6
MINOBU, Iwaki1∗ ; KATAOKA, Ryuho2 ; WATANABE, Masakazu3 ; FUJITA, Shigeru4 ; TANAKA, Takashi3 ;YUKIMATU, Akira sessai2 ; HOSOKAWA, Keisuke5 ; GROCOTT, Adrian6
1

九州大学大学院理学府地球惑星科学専攻, 2 国立極地研究所 総合研究大学院大学, 3 九州大学大学院理学研究院, 4 気象庁
気象大学校, 5 電気通信大学大学院情報理工学研究科, 6 University of Leicester
1
Department of earth and planetary sciences, Faculity of sciences, Kyushu University, 2 National institute of polar research SOKENDAI (The Graduate University for Advanced Studies), 3 Graduate School of Sciences, Kyushu University, 4 MeteorologicalCollege, Japan Meteorological Agency, 5 Department of Communication Engineering and Informatics, University of ElectroCommunications, 6 University of Leicester
電離圏 2 セル対流は主に惑星間空間磁場（IMF）南北方向成分 (BZ ) により制御されるものとして知られている。IMF
が南向きのとき、昼側の低緯度境界層におけるいわゆる Dungey のリコネクションにより、電離圏では IMF BZ の大きさに比例する 2 セル対流が励起される。これに対し IMF 北向きのときには 2 セル対流は弱まり、IMF BZ にはほとんど依存しない太陽風-磁気圏間の粘性相互作用が残ると理解されている。しかし Milan（2004）はやや異なる描像を得た。IMF
BZ の関数として極冠域対流ポテンシャル差を求めた結果、北向きに対して平均的に 25kV 程度の対流を見出し、対流への粘性相互作用寄与は˜10kV 程度であるものとし、IMF 北向き時の対流は夜側リコネクションと昼側高緯度リコネクションの混合であると結論づけている。そこで我々は SuperDARN の統計データベース [Grocott et al., 2009] を用いて、特に弱い北向き IMF に対する電離圏対流の応答を系統的に調べた。その結果、IMF の絶対値が 1nT 未満のとき、1nT 以上に比べて電離圏対流が強化される傾向を発見した。
上述の特殊な電離圏対流の機構を解明するため、グローバル MHD シミュレーションを用いて IMF 絶対値が 1nT 未
満の IMF に対する磁気圏-電離圏対流系を再現した。電離圏対流の強化は観測と同様にみられ、その原因は IMF の弱化によって磁気圏ダイナモがかえって強化されるためだと判明した。強い北向き IMF に対しては、マグネトシースとカスプの間に磁気圧が強い領域があり、これがシースからのプラズマ侵入を防いでいる。しかし、弱い北向き IMF に対してはその領域は消失する。この強磁気圧領域の消失はカスプ圧力の上昇を促し、カスプ-マントル境界領域に J・E が負である
ダイナモ領域の形成を促進する。そのダイナモによって沿磁力線電流は強化され電離圏対流もともに強化される。この機構による磁気圏ダイナモは、一般的描像であるダンジーサイクル [Dungey,1961] や粘性相互作用とは異なるものである。
マウンダー極小期のような太陽活動のグランドミニマムでは惑星間空間磁場が極端に弱まると考えられる。グラン
ドミニマムでは上述のような弱い北向き IMF が長期間継続する可能性があり、本研究は将来のグランドミニマムにおける地球磁気圏応答の予測に役立てることができる。

キーワード: MHD シミュレーション, 極端宇宙天気, 電離圏、磁気圏対流
Keywords: MHD simulation, severe space weather, M-I convection

1/1

PEM07-P04

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

SuperDARN studies on possible grand minimum influences on geospace environment
SuperDARN studies on possible grand minimum influences on geospace environment
行松 彰 1∗YUKIMATU, Akira sessai1∗
1
1

国立極地研究所、総合研究大学院大学, 2 総合研究大学院大学
NIPR, SOKENDAI, 2 SOKENDAI

The current unusual solar cycle is thought possibly to be the beginning of so-called Grand-Minimum period when solar activity stays at a very low level for a considerably long period. If this is the case, geospace environment (e.g., solar wind energy
input and high energy particles distribution) might change largely and consequently resulting in e.g., less frequent storms andsubstorms, shrunk polar cap and auroral oval and unexpected environmental changes in upper atmosphere or even global climatechanges. Such a view is one of the important scientific issues in new SCOSTEP VarSITI program (2014-2018).
SuperDARN HF radar network is a powerful tool to monitor fundamental ionospheric physical parameters to investigate global
electric potential maps and the dynamics of ionospheric and magnetospheric plasma convection under a variety of solar wind andmagnetospheric/ionospheric conditions.
SuperDARN HF radar network and various ground-based electro-magnetic field/waves and optical instruments at manned andunmanned stations have been deployed in Antarctic region - which are powerful and unique tools to study storms, substorms
and M-I (magnetosphere-ionosphere) coupling processes. Using these instrumental setup, the influence of current solar activity
changes on storms, substorms and a variety of coupling processes in Earth’s geospace environment should be investigated at thisopportunity by collaborating with in-situ satellite measurements (e.g., THEMIS, VAP, ERG) and theoretical researches.
How SuperDARN and NIPR Space and Upper Atmospheric Sciences Research Group can contribute to this particular important studies and what can be expected to be done during JARE (Japanese Antarctic Research Expedition) project phase IX
period (2016-2022) will be discussed, and how polar cap sizes and cusp latitudes, global convection strength and cross polar cap
potential have behaved depending on the past solar cycle activities and under current solar activity will be studied and shown
mainly using long term global SuperDARN observation data and influences of possible grand minimum will be discussed.
キーワード: SuperDARN, グランドミニマム, 低太陽活動期, 極域超高層大気, 電離圏対流, 領域間結合
Keywords: SuperDARN, Grand Minimum, low solar activity, polar upper atmosphere, ionospheric convection, cross-region
coupling

1/1

PEM07-P05

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

MAGDAS ネットワークによって観測された高速太陽風条件下での磁気赤道 Pc 5 の特徴
Characteristics of equatorial Pc 5 observed by the MAGDAS network under high-speed
solar wind conditions
秋本 開成 1∗ ; 藤本 晶子 2 ; 吉川 顕正 1 ; 魚住 禎司 2 ; 阿部 修司 2
AKIMOTO, Kaisei1∗ ; FUJIMOTO, Akiko2 ; YOSHIKAWA, Akimasa1 ; UOZUMI, Teiji2 ; ABE, Shuji21

九州大学大学院 理学府 地球惑星科学専攻, 2 九州大学 国際宇宙天気科学・教育センター
Department of Earth and Planetary Sciences Graduate school of Sciences Kyushu University, 2 International Center for Space
Weather Science and education

1

While investigating auroral latitude Pc 5 pulsations, Baker et al. (2003) and Mathie and Mann et al. (2001) found that these
pulsations have a good correlation with the solar wind flow speed. Also, Mathie and Mann et al. (2000) found that auroral
latitude Pc 5 is related to relativistic electron flux variation in the radiation belt. There are many studies about the characteristics
of auroral latitude Pc 5, while equatorial Pc 5 received little attention because there are fewer observation points in the equatorial
region. So, we investigated the characteristics of equatorial Pc 5 under high-speed solar wind conditions by using the datafrom dip equator stations of the MAGDAS/CPMN network (Kyushu University) during 2005/01/01 ˜2013/12/31. We foundthat electron flux enhancement is preceded by an intense activity of Pc 5 at the dayside equatorial MAGDAS stations during
2010/08/24˜2010/08/27. Reeves et al. (2003) showed that different types of relativistic electron flux variation are observed after
geomagnetic disturbances such as magnetic storm (i.e. not only increase type but also no-change type and decrease type).We
statistically analyzed the dependence of equatorial Pc 5 pulsations on the relativistic electron flux variation.
キーワード: MAGDAS, 磁気赤道, Pc 5
Keywords: MAGDAS, dip equator, Pc 5

1/1

PEM07-P06

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

太陽風パラメータを入力としたオーロラ活動指数の変動予測アルゴリズムの開発
Prediction of the Auroral Electro jet index from the solar wind
山本 凌大 1∗ ; 三好 由純 1 ; 宮下 幸長 1 ; 町田 忍 1
YAMAMOTO, Ryota1∗ ; MIYOSHI, Yoshizumi1 ; MIYASHITA, Yukinaga1 ; MACHIDA, Shinobu1
11

太陽宇宙環境研究所, 2 名古屋大学
STEL, 2 Nagoya Univ.

オーロラ活動およびサブストームの指標としてオーロラ指数（AU, AL, AE）があるが、その変動の予測は今後の宇宙環境の変化を把握することにつながるため宇宙天気予報の観点から重要な課題である。そのため、本研究では、Goertz etal.(1993) の開発したアルゴリズムをもとに、太陽風パラメータを入力として AU および AL 指数の変化を計算するコードの開発を行っている。これまでの開発および初期的な試験として、2000 年〜2008 年の ACE 衛星の観測値を入力として 1
年間ごとに長期的な AU 指数の変化の計算を行った。開発したモデルの性能を確認するためにスキルスコアの計算を行ったところ、最大で 0.8 程度であった。本講演では、開発したモデルの概要、および様々な太陽風を入力として AU、AL 指数の計算を行った計画を報告するとともに、AU、AL 指数の再現性との太陽風との関係についても報告する予定である。

キーワード: AU 指数, ＡＥ指数, Ａ L 指数, 宇宙天気
Keywords: AU index, AE index, AL index, Space weather

1/1PEM07-P07

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

1900-2014 年における太陽風の気候影響の相関地図による解析
Analyzing the influence of the solar wind on climate during 1900-20014 using correlationmaps
伊藤 公紀 1∗ ; 河野 翔 1
ITOH, Kiminori1∗ ; KAWANO, Shoh111

横浜国立大学環境情報研究院
Yokohama National University

我々は、太陽風の気候影響を調べるために、地磁気擾乱指数（aa 指数）と地表気温との相関やテレコネクションパター
ン (北極振動、太平洋十年規模振動など) との関係を、相関地図（相関係数の地理的分布）を用いて検討している。
相関を求める際、QBO (赤道域成層圏準二年振動) の位相に基づく層化が本質的に重要であることが分かっているが、位相の見積もりの信頼性が高い期間は 1942 年からである。しかし、1900 年まで遡って QBO の位相を推定した報告もあるので、ここではこのデータを利用して 1900 年から 2014 年までの期間について解析を行った。相関の時間窓は主として 20 年とした。
1942 年からの期間について観測されたテレコネクションパターンとの類似は、1900 年から 1941 年の期間についても見られた (図 1 参照)。これにより、1900 年から一貫して、太陽風はテレコネクションパターンに (従って気候に) 大き
な影響を与えていることが分かった。なお、1942 年〜2014 年で観測された長期間に亘って高い相関を保つ「特異地点」（例えば太平洋中央部の逆相関）では、1930 年頃に相関の符号が逆転していた。

キーワード: 太陽風, 気温, テレコネクションパターン, 北極振動, 太平洋十年規模振動
Keywords: solar wind, temperature, teleconnection pattern, Arctic Oscillation, Pacific Decadal Oscillation

1/1

PEM07-P08

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

対流圏及び成層圏の気温に対するオゾンと太陽風の影響
Influence of solar wind and ozone on the temperatures of the troposphere and stratosphere
山下 和良 1∗YAMASHITA, Kazuyoshi1∗
1
1

横浜国立大学大学院環境情報学府
YOKOHAMA National University

太陽磁気活動と地球大気の温度変化は相関関係にあることは間違いないが、その原因は明らかではない。この問題に対して今までの研究成果 [1] に基づき、太陽風とオゾンが地球大気に与える影響について分析検討する。
今回、太陽風の影響を確認するためＡＥ及びＤｓｔ指数データを使用し、オゾン全量と対流圏及び成層圏の気温の変化を解析した。
なお、解析を進めるにあたって次に点に注意した。低緯度でのオゾンに対するＥＰＰ−ＮＯｘの影響がＵＶ紫外線に匹敵する可能性がある [Callis et al.,2000,2001;Langematz et al.,2005;Rozanov et al.,2005]。低緯度で生成されたオゾンは冬極域に輸送されるため、ＥＰＰ−ＮＯｘが極域のオゾン減少に影響を与えている。
解析結果として、極域における５００ｈＰａ面の気温と８５０ｈＰａ面の気温から計算したショワルター安定指数（ＳＳＩ）は、ＡＥ指数と相関関係にあり、特にＱＢＯが西風の時にその傾向が強い。このことは太陽風に伴う高エネル
ギー粒子の増加が、極域おける成層圏オゾンを減少させ、対流圏に到達する日射量を増加させることで、大気の安定度に影響を与えている可能性がある。
以上のことから太陽風の影響による成層圏オゾンの変化は、対流圏の気候に影響を与えていることを示唆している。

[1] 伊藤公紀、地球惑星科学連合大会２００８−２０１４

キーワード: 太陽風, オゾン, 圏界面, ＡＥ指数, Ｄｓｔ指数, 大気安定度
Keywords: solar wind, ozone, tropopause, AE index, Dst index, stability of atmosphere

1/1

PEM07-P09

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

自動検出モジュールを用いた太陽コロナホールの生成・消滅過程の研究
Study of process of the generation and disappearance of coronal holes using tracking
module加納 大空 1∗ ; 今田 晋亮 1 ; 町田 忍 1
KANO, Ohzora1∗ ; IMADA, Shinsuke1 ; MACHIDA, Shinobu1
11

太陽地球環境研究所
Solar-Terrestrial Environment Laboratory, Nagoya University

SDO(Solar Dynamics Observatory) 衛星に搭載された４つの望遠鏡群 (Atmospheric Imaging Assembly : AIA) の観測デー
タおよび２機の STEREO(Solar TErrestrial RElations Observatory) 衛星に搭載された太陽圏探査装置 (Sun Earth Connection
Coronal and Heliospheric Investigation : SECCHI) の観測データから太陽コロナホールの時間変化を追う自動検出モジュールを作成した。また、そのモジュールを用いて太陽コロナホールの生成・消滅過程の解析を行った。今回用いた自動検出モジュールは以下の手順で太陽コロナホールを自動検出する。
(1) ３つの衛星の太陽観測データをつなぎあわせ、太陽全面のメルカトルマップを作成(2) 明度による閾値に基づいてコロナホールの候補となる領域を検出(3) 大きさによる閾値に基づいて微小領域を排除し、追跡対象となる領域を決定(4) 作成したメルカトルマップに決定した領域を指定し追跡
本研究では太陽 360 度全面を常に観測することで、連続的に太陽コロナホールを追跡することが可能である。そこから、半年にわたって同一の太陽コロナホールがどのように生成し、どのように消滅するかを考察し、報告する。

キーワード: コロナホール, 自動検出, メルカトルマップ
Keywords: coronal hole, automatic detection, mercator map

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PEM07-P10

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

DSCOVR からのリアルタイム太陽風データの受信と利用
Reception of real-time solar wind data from DSCOVR and its application
亘 慎一 1∗ ; 久保 勇樹 1 ; 石井 守 1
WATARI, Shinichi1∗ ; KUBO, Yuki1 ; ISHII, Mamoru1
1
1

情報通信研究機構
National Institute of Information and Communications Technology

2015 年 2 月 11 日 (UT) に DSCOVR (Deep Space Climate Observatory) が米国のケープカナベラルから打ち上げられた。
DSCOVR は、NASA の科学衛星 ACE (Advanced Composition Explorer) の後継機で、初の宇宙天気のための実用ミッションとなった。打ち上げ後、約 110 日かけてラグランジュ点（L1）に到達する。DSCOVR は、磁場 3 成分の 1 秒値と 1 分値、速度 3 成分、温度、密度の 3 秒値と 1 分値をリアルタイムで提供する。DSCOVR からのデータの概要と太陽風領域の識別などデータの利用について報告を行う。
キーワード: 太陽風, 宇宙天気, L1, ACE, DSCOVR
Keywords: solar wind, space weather, L1, ACE, DSCOVR

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PEM07-P11

会場:コンベンションホール

時間:5 月 26 日 18:15-19:30

SCOSTEP-WDS ワークショップ 太陽地球系変動研究に向けた国際データ組織
SCOSTEP-WDS Workshop on Global Data System for the Study of Solar-Terrestrial
Variability
渡辺 堯 1∗WATANABE, Takashi1∗
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ICSU-ＷＤＳ国際プログラムオフィス
ICSU-WDS International Programme Office

太陽地球系物理学・科学委員会 (SCOSTEP）と ICSU 世界データシステム（WDS）の合同研究会として、超高層物理学分野を含む太陽地球系観測データの品質管理、長期保全、国際共有、データの認証と再利用、データ提供者の正当な評
価システムの確立等に向けた活動において、両者の連携を強化に向けた情報交換と協議を行う。また SCOSTP の研究事業である VarSITI (Variability of the Sun and Its Terrestrial Impact) で定めた解析期間における超高層観測データについて、
IUGONET などの国際的データシステムによってオンラインで解析できる環境を提供し、現象の理解を進める。会期は2015 年 9 月 28 − 30 日、会場は（独）情報通信研究機構。
キーワード: 国際科学会議（ICSU）, 太陽地球系物理学・科学委員会, 世界データシステム, VarSITI, データ, ワークショッ
プ
Keywords: ICSU, SCOSTEP, WDS, VarSITI, Data, Workshop

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