資料7-H

Japanese URSI Commission H (Waves in Plasmas)
Activity Report
July - October, 2013[1] Status of projects related with plasma wave observation
1. NICT Science Cloud
NICT Science Cloud has been developed forspace plasma studies. Three outstanding
developments were achieved during thisperiod.
(1) Large Scale data processing technique
for space plasma data analysis isdeveloped on the NICT Science Cloud.
This technique is applied for two typesof space plasma data, GEOTAIL PWI
data and KAGUYA PWI data, toachieve more than 100 times higher speed data processing than via
traditional way.
(2) A Data collection (transfer) system, named WONM (World-wide Observation
Network Monitoring) system is complete and under operation. We set thissystem to more than 10 observatories, including Antarctica and equatorial
observatories for ionospheric observations.
(3) Data and program storage service is ready. We could successfully store
several types of plasma wave data and other STP (Solar-Terrestrial Physics)
data on the NICT Science Cloud, including GEOTAIL, AKEBONO, KAGUYA
satellites.

[2] Recent Meetings
1.

11th International School/Symposium for Space Simulations (ISSS-11), Jhongli City,
Taiwan, July 21-27, 2013.

2.

IAGA 2013, Mérida, Yucatán, México, August 26-31, 2013.

3.

AP-RASC 2013, Taipei, Taiwan, September 3-7, 2013.

[3] Future Meetings
1. COSPAR Symposium on “Planetary Systems of our Sun and other Stars, and the
Future of Space Astronomy”, Bangkok, Thailand, November 11-15, 2013.

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資料7-H

2. International CAWSES (Climate and Weather of the Sun-Earth System)-II
Symposium, Nagoya, Japan, November 18-22, 2013.
3. 6th VERSIM (VLF/ELF Remote Sensing of the Ionosphere and Magnetosphere)
workshop 2014, 20-23 January 2014, University of Otago, Dunedin, New Zealand.

[4] Recently Published Papers (July 2013 – October 2013)
1.

Murata, K. T., Watanabe, H., Ukawa, K., Yamamoto, K. and Zettsu, K., The NICT
Science Cloud -- A Challenge of Science Data Crawling via NICT Science Cloud andDiscussion

towardLinked

Open

Data

--(in

Japanese),

IEICE-AI2013-18,

IEICE-SC2013-12, IEICE-113, No.178(AI), No.179(SC), pp.19-24, 2013.
In the Solar-Terrestrial Physics (STP), it is pointed out that circulation andutilization of observation data among researchers are insufficient. One of thereasons is that the data formats of STP observation data are not common. This is
not only the issue of STP data but also of other natural science data. To archive
interdisciplinary researches, we need to overcome this circulation and utilization
problems. Under such a background, the Solar-Terrestrial data Analysis andReference System (STARS) has been designed and developed by the authors’group. In the present study, we designed meta-data of the STARS along with the
RSS1.0 document. In order to describe the meta-data of the STARS beyond
RSS1.0 vocabulary, we defined original vocabularies for the STARS resources
using RDF Schema. Our system works as follows. The RSS1.0 documents
generated on data sites are automatically collected by a meta-data collection
agent. The agent extracts meta-data to store them in an XML database. The XML
database provides advanced retrieval processing that has considered property andrelation.
2.

Isoda, F., Murata, K. T., Fukazawa, K., Watanabe, H., Ebihara, Y., Saita, S., Kubota,
Y. and Kimura, E., High Time Resolutional Visualization of Earth’s MHD
Simulation(in Japanese), Journal of Visualization Society of Japan, Vol.33,
Suppl.No.2, pp.247-248, 2013.
The high time and spatial resolution visualizations in 3D of the global MHD
simulations are presented. The Virtual Aurora, is a tool designed based on the
AVS, is developed on the purpose of adapting to the parallel processing with the
distributed file system, Gfarm/Pwrake to process huge amount of simulation data

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資料7-Hfiles. The new technique is included, as the tracing of fluid elements. It will
helpful for understanding the convection in the magnetosphere.
3.

Murata, K. T., Isoda, F., Fukazawa, K., Watanabe, H., Tatebe, O., Tanaka, M.,
Kimura, E., Yamamoto, K., Ukawa, K., Muranaga, K. and Suzuki, Y., A New
Visualization Method of Big Data Era on Science Cloud(in Japanese), Journal of
Visualization Society of Japan, Vol.33, Suppl.No.2, pp.255-256, 2013.
The NICT Science Cloud is a cloud system designed for scientific researches, andexpected as a new infrastructure for big data sciences. Not only parallelization of
CPU as in super-computers, but I/O and network throughput parallelization are
crucial for the big data science. A high-performance visualization system isconstructed on the NICT Science Cloud using Gfarm/Pwrake middleware. We
examined performance of this parallel visualization environment for a set ofcomputer simulation with 1000 files (2.3TB in all). After setting higher priority toaccess to local file on local disk, we finally achieved 124 times higher visualization
using 192 core cpu.

4.

Watanabe, H., Murata, T., Isoda, F., Tatebe, O., Tanaka, M., Kimura, E., Ukawa, K.,
Muranaga, K. andSuzuki, Y., New Visualization in Big Data Era on Science

Cloud(in Japanese), Journal of Visualization Society of Japan, Vol.33, Suppl.No.2,
pp.71-72, 2013.
Duringthese

50years,

along

with

appearance

anddevelopmentofsuper-computers, numerical simulation is considered to be a third methodology
for science, following theoretical (first) and experimental and/or observational(second) approaches. The variety of data yielded by the second approaches has
been getting more and more. This paper is to propose a cloud system for
informatics, which has been developed at NICT (National Institute of Information
and Communications Technology), Japan. We first introduce the NICT science
cloud. We next demonstrate the efficiency of the science cloud, showing several
scientific results which we achieved with this cloud system. Through thediscussions and demonstrations, the potential performance of sciences cloud will
be revealed for any research fields.
5.

Isoda, F., Murata, T., Watanabe, H., Fukazawa, K., Yamamoto, K., Kubota, Y.,
Kasai, Y., Sato, S., Ukawa, K., Muranaga, K., Suzuki, Y., Kurosawa, T., Kimura, E.,
Tatebe, O. and Tanaka, M., NICT Science Cloud: Big-data Analyses via Parallel and369/384

資料7-H

Distributed Processing Technique for Earth and Space Science(in Japanese),
IEICE-PRMU2013-62, IEICE-113, No.230, pp.29-34, 2013.
Science cloud is a cloud system designed for scientific researches, and expected asa new infrastructure for big data sciences. Not only parallelization of CPU as insuper-computers, but I/O and network throughput parallelization are crucial forthe big data science. One of the typical structures of science cloud is a scalable
cluster in which multiple clusters in a cloud are connected with high-speed
network. In the present study, we study a performance of parallelization of both
CPU and I/O inside a cloud as a first step to the high performance scalable
clusters. In case with few processes executed on each computational node (server),parallelization efficiency is almost 100%. This high efficiency is expected tomaintain in larger-scale cluster systems such as those with 30 servers. On theother hand, under the condition of multi-processes on each node, the present
parallelization does not show good performance due to the congestions of I/O.
Parallelization efficiency is as low as 15.6. New techniques of decentralization of
I/O within each node are required in the next step.
6.

Murata, T., Isoda, F., Watanabe, H., Ukawa, K., Muranaga, K., Suzuki, Y.,
Kurosawa, T., Kimura, E., Tatebe, O., Tanaka, M., Yamamoto, K., Nagatsuma, T.,
Tsugawa, T., Sato, S. and Kasai, Y., NICT Science Cloud: Data Collection, Databaseand Data Processing of Global Earth and Space Observation Networks(inJapanese), IEICE-PRMU2013-61, IEICE-113, No.230, pp.23-28, 2013.
This paper is devoted to present an operation system to acquire, to transfer and to
storage data for world-wide observation networks, which is named as“NICTY/DLA” and “WONM (Wide-area Observation Network Monitoring) system,
developed in NICT (National Institute of Information and Communications
Technology). These systems provide us with easier management of data collection
than legacy systems by means of autonomous system recovery, periodical statemonitoring, and dynamic warning procedures. We have equipped world-wide
observatories for space weather prediction and research works with this system
connected with the NICT Science Cloud. We will discuss this challenging system,
especially from the viewpoint that we easily operate world-wide observatories on a
web application.

7.

Nagatsuma, T., Murata, K. T., Yamamoto, K., Tsugawa, T., Kitauchi, H., Kondo, T.,
Ishibashi, H., Nishioka, M. and Okada, M., Operation of data acquisition, transfer

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資料7-Hand storage system for world-wide observation networks, International Forum on
Polar Data Activities in Global Data Systems, Program and Abstracts, pp.110-111,
2013.
This paper is devoted to present an operation system to acquire, to transfer andto storage data for world-wide observation networks, which is named as “WONM(Wide-area Observation Network Monitoring) system, developed in NICT
(National Institute of Information and Communications Technology). This systemprovides us with easier management of data collection than legacy systems bymeans of autonomous system recovery, periodical state monitoring, and dynamic
warning procedures. We have equipped world-wide observatories for space
weather prediction and research works with this system connected with the
NICT Science Cloud. Demonstration and discussion will be presented concerningwith this challenging system, especially from the viewpoint that we easily
operate world-wide observatories on a web application.
8.

Murata, K. T., Watanabe, H., Yamamoto, Isoda, F., Kimura, E., Tatebe, O., Tanaka,
M., Ukawa, K., Muranaga, K. and Suzuki, Y., The NICT Science Cloud: distributed
storage system and parallel data processing applicable for polar research data,
International Forum on Polar Data Activities in Global Data Systems, Program and
Abstracts, pp.108-109, 2013.
Data-oriented science is considered as the forth paradigm for coming big data
science, including polar research. The NICT Science Cloud is designed andconstructed as a basis for data-oriented science since 2010. In the present paper,
we discuss the basic concepts behind the NICT Science Cloud, especially focusing
on big-data processing. We demonstrate information and communication
technologies (ICT) designed to transfer, steward, process and publicize large-scaledata acquired and analysed in solar-terrestrial physics.

9.

Y. Katoh and Y. Omura, Effect of the background magnetic field inhomogeneity on
generation processes of whistler-mode chorus and broadband hiss-like emissions, J.
Geophys. Res., doi: 10.1002/jgra.50395, 2013.
By a series of self-consistent electron hybrid code simulations, we study the effectof the background magnetic field inhomogeneity on the generation process ofwhistler-mode chorus emissions. Chorus with rising tones are generated throughnonlinear wave-particle interactions occurring around the magnetic equator. The
mirror force plays an important role in the nonlinear interactions, and the spatial

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資料7-Hinhomogeneity of the background magnetic field is a key parameter of the chorus
generation process. We have conducted numerical experiments with different
spatial inhomogeneities to understand properties of the chorus generation
process. We assume the same initial condition of energetic electrons at themagnetic equator in all simulation runs. The simulation results reveal that the
spectral characteristics of chorus significantly vary depending on the magnetic
field inhomogeneity. Whistler-mode emissions are generated and propagate awayfrom the equator in all simulation runs, but distinct chorus elements with rising
tones are only reproduced in the cases of small inhomogeneities. In thesimulation that had the smallest inhomogeneity, we find excitation of broadband
hiss-like emission (BHE) whose amplitudes are comparable to discrete chorus
elements found in other simulation runs.
10. D. Summers, R. Tang, Y. Omura, and D. H. Lee, Parameter spaces for linear andnonlinear whistler-mode waves, Phys. Plasmas, 20, 072110; doi: 10.1063/1.4816022,
2013
We examine the growth of magnetospheric whistler-mode waves which comprises
a linear growth phase followed by a nonlinear growth phase. We constructtime-profiles for the wave amplitude that smoothly match at the transition
between linear and nonlinear wave growth. This matching procedure can only
take place over a limited “matching region” in ðNh=N0; ATÞ-space, where AT isthe electron thermal anisotropy, Nh is the hot (energetic) electron number density,
and N0 is the cold (background) electron number density. We construct thismatching region and determine how the matching wave amplitude varies
throughout the region. Further, we specify a boundary in ðNh=N0; ATÞ-spacethat separates a region where only linear chorus wave growth can occur from theregion in which fully nonlinear chorus growth is possible.

11. Y. Miyoshi, R. Kataoka, Y. Kasahara, A. Kumamoto, T. Nagai, and M. F. Thomsen
High-speed solar wind with southward interplanetary magnetic field causes relativistic
electron flux enhancement of the outer radiation belt via enhanced condition of whistler
waves,

Geophys. Res. Lett., 40, 1–6, doi:10.1002/grl.50916, 2013

Relativistic electron flux in the outer radiation belt tends to increase during the high-speed
solar wind stream (HSS) events. We demonstrate that during HSS events with the southward
interplanetary magnetic field (IMF)-dominant HSS (SBz-HSS), relativistic electrons areaccelerated by whistler mode waves; however, during HSS events with the northward372/384

資料7-HIMF-dominant HSS, this acceleration mechanism is not effective. The differences in the
responses of the outer radiation belt flux variations are caused by the differences in thewhistler mode wave–electron interactions associated with a series of substorms. During
SBz-HSS events, hot electron injections occur and the thermal plasma density decreases dueto the shrinkage of the plasmapause, causing large flux enhancement of relativistic electrons
through whistler mode wave excitation. These results explain why large flux enhancement ofrelativistic electrons tends to occur during SBz-HSS events.

12. K. Sakaguchi, Y. Kasahara, M. Shoji, Y. Omura, Y. Miyoshi, T. Nagatsuma, A. Kumamoto,
A. Matsuoka,
belts,

Akebono observations of EMIC waves in the slot region of the radiation

Geophys. Res. Lett., 40, 1-5, doi:10.1002/2013GL058258, 2013

Akebono observed electromagnetic ion cyclotron (EMIC) waves in the deep innermagnetosphere at L = 2.5 – 5 at altitudes of 3,300 − 8,700 km. The mode conversion, i.e., L
mode (He+ band) → R mode (He+ band) → L mode (O+ band) was clearly identified
from the equator to high latitudes. In addition, rising tone structures are found, recently
identified as EMIC triggered emissions, which could lead to bursty precipitation ofrelativistic electrons. First, the ion composition ratio (H+, He+, O+) = (83%, 16%, 1%) are
estimated from polarization analysis. Second, minimum resonant electron energies with theobserved EMIC waves and triggered emissions are estimated to be ∼1–10 MeV. The satellite
trajectory during the wave observation was primarily through the slot region of electron
radiation belts. The collocation implies possible contribution of EMIC waves to formation of
the slot region of radiation belts after a magnetic storm.
13. M. N. Nishino, M. Fujimoto, Y. Saito, H. Tsunakawa, Y. Kasahara, M. Kawamura,
M. Matsushima, F. Takahashi, H. Shibuya, H. Shimizu, Y. Goto, K. Hashimoto, Y.
Omura, A. Kumamoto, T. Ono, S. Yokota, Type-II Entry of Solar Wind Protons into
the Lunar Wake: Effects of Magnetic Connection to the Night-side Surface,

Planetary and Space Science, 87, 106-114, doi:10.1016/j.pss.2013.08.017, 2013.
Recent observations by KAGUYA revealed that type-II (T2) entry of the solar
wind protons into the near-Moon wake occurs when the IMF is dominated by the
non-radial components (i.e. BY and/or BZ). Nishino et al. (2013) categorized T2entry into two cases; T2 entry with magnetic connection to the lunar surface(T2MC) and T2 entry into magnetically detached regions (T2MD). Strong
electron acceleration (up to several hundred eV to 1 keV) along the magnetic field
associated with the T2 entry is prominent when the field line has its both ends inthe solar wind, that is, when the magnetic field is detached from the lunar

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資料7-Hsurface (T2MD).

On the other hand, no significant electron acceleration is foundin the T2MC cases although an enhancement of the electron flux associated with
the T2 proton entry is evident. They also reported that the T2 entry process takes
place even under radial (BX-dominated) IMF condition. These results indicate
that, while the T2 entry of solar wind protons into the wake itself does not
require a special IMF condition but is a rather general phenomenon, thecharacteristic energy of associated electrons does show a strong dependence on
the magnetic connectivity to the lunar surface.
14. K. H. Lee, Y. Omura, and L. C. Lee, Electron acceleration by Z-mode andwhistler-mode waves, Phys. Plasmas, 20, 112901; doi: 10.1063/1.4829439, 2013.
We carried out a series of particle simulations to study electron acceleration by
Z-mode and whistler-mode waves generated by an electron ring distribution. The
electron ring distribution leads to excitations of X-mode waves mainly in theperpendicular direction, Z-mode waves in the perpendicular and parallel
directions, and whistler-mode waves mainly in the parallel direction. The parallelZ- and whistler-mode waves can lead to an effective acceleration of ring electrons.
The electron acceleration is mainly determined by the wave amplitude and phasevelocity, which in turn is affected by the ratio of electron plasma to cyclotron
frequencies. For the initial kinetic energy ranging from 100 to 500 keV, the peakenergy of the accelerated electrons is found to reach 2–8 times the initial kinetic
energy. We further study the acceleration process by test-particle calculations inwhich electrons interact with one, two, or four waves. The electron trajectories in
the one-wave case are simple diffusion curves. In the multi-wave cases, electrons
are accelerated simultaneously by counter-propagating waves and can have ahigher final energy.
15. Y. Omura and Q. Zhao, Relativistic electron microbursts due to nonlinear
pitch-angle scattering by EMIC triggered emissions, J. Geophys. Res., doi:
10.1002/jgra.50477, 2013.
We show that the anomalous cyclotron resonance between relativistic electronsand electromagnetic ion cyclotron (EMIC) triggered emissions takes place very
effectively near the magnetic equator because of the variation of the ambient
magnetic field. Efficient precipitations are caused by nonlinear trapping ofrelativistic electrons by electromagnetic wave potentials formed by EMIC
triggered emissions. We derive the necessary conditions of the wave amplitude,

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資料7-Hkinetic energies, and pitch angles that must be satisfied for the nonlinear wave
trapping. We have conducted test particle simulations with a large number ofrelativistic electrons trapped by a parabolic magnetic field near the magnetic
equator. In the presence of coherent EMIC-triggered emissions with increasing
frequencies, a substantial amount of relativistic electrons is trapped by the wave,
and the relativistic electrons at high pitch angles are guided to lower pitch angles
within a short time scale much less than a second, resulting in rapid precipitationof relativistic electrons or relativistic electron microbursts.
16. M. Shoji and Y. Omura, Triggering process of electromagnetic ion cyclotron rising
tone emissions in the inner magnetosphere, J. Geophys. Res., 118, 5553–5561,
doi:10.1002/jgra.50523, 2013.
Spacecraft

observations

andsimulations

show

generationofcoherent

electromagnetic ion cyclotron (EMIC) triggered emissions with rising tone
frequencies. In the inner magnetosphere, the spontaneously triggered EMIC
waves are generated by the energetic protons with large temperature anisotropy.
We reproduced EMIC triggered emissions in the Earth’s magnetosphere by real
scale hybrid simulations with cylindrical magnetic geometry. We obtained
spontaneously triggered nonlinear EMIC waves with rising frequencies in the H+band of the EMIC dispersion relation. The proton holes in the phase space areformed. We have also derived the theoretical optimum wave amplitude fortriggering process of the EMIC nonlinear wave growth. The optimum wave
amplitude and the nonlinear transition time show a good agreement with thepresent simulation result. The nonlinear wave growth over a limited time forms a
subpacket structure of a rising tone emission. The formation process of a
subpacket is repeated because of a new triggering wave generated by thephase-organized protons, which are released from the previous subpacket. Then,the EMIC triggered emission is formed as a train of subpackets generated at
different rising frequencies.

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