PCG31-01

Room:202

Time:May 27 15:15-15:30

Current status and future direction of sounding rocket experiments in Japan
ABE, Takumi1∗
1Japan Aerospace Exploration Agency

Sounding rocket is an effective platform which provides opportunity to make a vertical sounding for a short period throughthe thermosphere, ionosphere and magnetosphere while satellite generally flies in a horizontal direction. In short, the sounding
rocket has a great advantage in conducting an instantaneous survey of the upper atmosphere in the vertical direction. The primaryobjectives of Japanese rocket experiments include various topics; studies of thermospheric, ionospheric, magnetospheric physics,
and astrophysics, microgravity experiment, demonstration of various instrument and technique, and advanced engineering experiments. Among these topics, the upper atmospheric physics is one of the most frequently explored targets.
For further understanding the upper atmosphere and ionosphere, sounding rocket will be inevitably needed. In particular, it is
the most effective platform to investigate a coupling between neutral atmosphere and plasma, in other words, coupling between
thermosphere and ionosphere, because it is only a platform which enables in-situ observation at 100-250 km altitudes where arole of collision rapidly changes. Advanced ground-based instruments to observe thermosphere and ionosphere are deployed andnow operational in many places in Japan, and those capability has a great advantage compared to other countries. Making use ofsuch an advantage, it becomes possible for Japan to conduct the most advanced experiment by coordinating the sounding rocket
and the ground-based observations. However, we cannot expect too much progress as long as we repeat similar observations. It
is highly required to adapt a new perspective to the future experiment to proceed to the next step from our current understanding.
Furthermore, it is desired to develop a new type of instrument which enables us to study the thermospheric and ionosphericphysics from a new point of view.
Another advantage of sounding rocket is that a proposed experiment can be achieved within a few years after a mission proposal is approved, while it takes more than three time longer in the satellite project. On the other hand, it should be noted thatit also takes several years to develop a new instrument. Therefore, it is necessary to make a plan by closely coordinating afuture experiment of the sounding rocket and the instrument development. In this presentation, we will also discuss what kind of
instrument should be developed in the future.

Keywords: souding rocket, Upper atmosphere, ionosphere

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PCG31-02

Room:202

Time:May 27 15:30-15:45

A multi-satellite formation flight mission for aurora observation
ASAMURA, Kazushi1∗ ; MIYOSHI, Yoshizumi2 ; SAKANOI, Takeshi3 ; HIRAHARA, Masafumi2 ;MATSUOKA, Ayako1
1

ISAS/JAXA, 2 Nagoya U., 3 Tohoku U.

In 2000s, Fast and Reimei satellite revealed fine-scale plasma particle and wave structures which are considered to be playing
a siginificant role in magnetoshere - ionosphere coupling. They carry plasma instuments with time resolution of tens of ms which
is much higher than previous. In particular, Reimei conducted plasma particle measurements togather with auroral imagings inwhich ionospheric footprints were captured. It provides us a hint for fine-scale spatial plasma structures in the auroral region
although it is a single-satellite platform. However, it is still difficult to investigate a dynamics of plasma processes by using thesimultaneous observations without wave measurements, like Reimei. It would be necessary to make a simultaneous observationof plasma particles and auroral emissions togather with waves, which is never made so far. We are planning a multi-satellite
formation flight mission for auroral observation. Main purpose of the mission is to reveal (1) time- and spatial-structures ofauroral particle accelaration caused by Alfven waves and field-aligned electric field, (2) energy transfer between plasma waves
and ions in supra-thermal energy range, and (3) fine-scale plasma structures which trigger global-scale changes and vice versa.
We will discuss possible mission configurations.
Keywords: Aurora, satellite mission

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PCG31-03

Room:202

Time:May 27 15:45-16:00

Science of Collisionless Shock Explorer
AMANO, Takanobu1∗ ; HOSHINO, Masahiro1 ; SAITO, Yoshifumi2 ; FUJIMOTO, Masaki2
1

University of Tokyo, 2 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency

The characteristic length scale of typical dilute space plasmas is much shorter than binary collision mean free path. A pronounced feature unique to such a collisionless plasma is that efficient energy and momentum transfer is mediated by plasma
waves. The plasma waves often reach to large amplitude, suggesting critical importance of nonlinear effects. In addition, it isoften found that a small fraction of particles acquire extremely large energies and forms a nonthermal tail.
A collisionless shock is a magnetohydrodynamic shock wave forms in a collisionless plasma, involving all the above mentioned intriguing features of the collisionless system. In the shock transition region, a cold upstream plasma is violently heated
via dissipation involving a lot of plasma waves excited simultaneously. The understanding of the dissipation process is extremelycomplicated due to its intrinsic strong nonlinearity and inhomogeneity. Although we know an ion-scale shock structure fromearly in-situ observations, recent measurements of plasma waves in and around the shock clearly indicate the importance ofsmall-scale substructures and nonlinear wave-particle interactions. However, the temporal resolution of distribution function
measurements with available satellites is not sufficient to understand the detailed shock dissipation processes.
In this talk, we discuss the scientific significance of collisionless shock physics that may be learned with high time resolution(1-10 msec) in-situ measurements of electron and ion distribution functions within the shock transition region along with recent
theory, simulations, and observations.
Keywords: collisionless plasma, shock wave, wave-particle interaction, particle acceleration

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PCG31-04

Room:202

Time:May 27 16:15-16:30

Importance of integrated data analysis for geospace science
MIYOSHI, Yoshizumi1∗ ; SEKI, Kanako1 ; HORI, Tomoaki1 ; MIYASHITA, Yukinaga1 ; KEIKA, Kunihiro1 ;SHOJI, Masafumi1 ; SEGAWA, Tomonori1 ; SHINOHARA, Iku2
1

Solar-Terrestrial Environment Laboratory, Nagoya University, 2 ISAS/JAXA

The geospace environment is characterized by dynamic process which link sun/solar wind to the changes in the near Earthspace environment. Many attractive phenomena in geospace occur in the inner magnetosphere, for example, enhancement ofring current that causes magnetic storms, and disappearance and rebuilding of the MeV electrons in the radiation belts. Insitu and ground-based observation systems provide various kinds of the observation data to support our understanding of thegeospace. Since the geospace is a complex coupled system and elementary process at different energies and regions affect andare affected by each other, the integrated analysis system is needed in order to address the interconnection of each elementary
process and to understand the geospace as a global coupled system. In order to realize such integrated analysis environment, the
ERG-Science Center operated by ISAS/JAXA and STEL/Nagoya University have developed the integrated data analysis system.
The standard data format and the common analysis software are a key technology for the system. The ERG project data arearchived with the NASA/CDF format and opened to the public, and the analysis procedures that are plug-in of the SPEDAS
are also developed. The data analysis system for the ERG project would be useful for not only the ERG project but also othergeospace missions, and the system should be a heritage for the future geospace mission. In this presentation, we describe current
activities of the ERG-Science center and the perspective on the integrated data analysis for the future geospace missions.
Keywords: integrated data analysis, satellite-ground based observations, future geospace mission

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PCG31-05

Room:202

Time:May 27 16:30-16:45

A Piggyback Micro-Satellite for Aurora Observation
SAITO, Yoshifumi1∗ ; MATSUNAGA, Saburo1 ; NAKAMURA, Yuya2 ; ASAMURA, Kazushi1 ; HIRAHARA, Masafumi3 ;KOJIMA, Hirotsugu4 ; SAKANOI, Takeshi5 ; MATSUOKA, Ayako1 ; SHIMOYAMA, Manabu3 ; YOKOTA, Shoichiro1
1

Institute of Space and Astronautical Science, 2 Axelspace Corporation, 3 Solar-Terretrial Environment Laboratory, Nagoya University, 4 Research institute for sustainable humanosphere, Kyoto university, 5 Planetary Plasma and Atmospheric Research Center, Tohoku University
Recently quite a number of 50kg-class micro-satellite has been developed. However, due to the limited function of the satellite
as well as the limitation in the mass of the payload instruments, 50kg-class micro-satellite that can make comprehensive measurements of space plasma including plasma particles, plasma waves and electro-magnetic field does not exist. The multi-point
in-situ measurements of space plasma by formation flying spacecraft have become usual in the field of Solar Terrestrial Physics(STP). In order to realize multi-point space plasma measurements by formation flying satellites with relatively small launchvehicle in Japan, it is indispensable to develop high performance micro satellite. 50kg-class micro-satellite for aurora observation will verify that even 50kg-class micro satellite can make world first class space plasma observation including magnetic
field, electric field, plasma waves, plasma particles and optical aurora observations. We are planning to launch a 50kg-classmicro-spacecraft as a piggyback satellite and to put the spacecraft into an orbit that crosses the auroral regions. If we succeed
in realizing this 50kg-class micro-satellite, it will also become possible for us to plan a future mission with 5 formation flying
spacecraft for aurora observation using a launch vehicle as small as Japanese Epsilon rocket. It will also give a way to realize
future larger scale formation flying spacecraft mission with affordable cost. Although a 50kg-class micro-satellite was used fora daughter spacecraft of the Russian spacecraft Interball, the micro-spacecraft did not have enough performance necessary forworld first class plasma in-situ measurements. The preliminary study on the piggyback micro-satellite for aurora observation is
being made by a scientists’ group who have been participating to the spacecraft missions such as REIMEI and ERG together
with ISAS Research Group on micro-satellite. This piggyback micro-satellite mission is a precursor of the future small-class or
medium-class spacecraft mission of Japanese STP community.
Keywords: Micro Satellite, Piggyback Satellite, Aurora

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PCG31-06

Room:202

Time:May 27 16:45-17:00

Auroral camera required in the future small satellite missions exploring the magnetosphereionosphere coupling processes
SAKANOI, Takeshi1∗ ; ASAMURA, Kazushi2 ; MIYOSHI, Yoshizumi3 ; HIRAHARA, Masafumi3 ;SAITO, Yoshifumi2
1

Graduate School of Science, Tohoku University, 2 Institute of Space and Astronautical Science, JAXA, 3 STEL, Nagoya University
We propose the conceptual design of auroral camera required for future small-scale satellite mission to be launched for understanding the magnetosphere-ionosphere coupling system and fine-scale aurora. Reimei satellite showed that the simultaneous
image-particle data are useful to investigate the fine-scale auroral dynamics, such as small-scale discrete aurora and time-varying
pulsating aurora. However, Reimei does not carry the wave and field detectors, and therefore it is hardly measure the field aligned
current, which is essential to understand the coupling process. Thus, the fundamental issues, such as the coupling process (timeand spatial variation) via dispersive Alfven wave, radio wave emission from the auroral acceleration region, the relationshipbetween large-scale auroral dynamics (like substorms) and small-scale aurora, etc., are still not understood.
We are now discussing on the possibilities for future small- and micro-scale satellites to understand the small-scale aurora andthe coupling system between magnetosphere and ionosphere. In this talk, we focus on the scientific targets to be solved by the
future satellite missions, and also show the conceptual design of auroral camera. These will be launched into a polar orbit at
low-earth-orbit (LEO) or at mid-altitudes up to a few thousands km. We consider that the following specifications are required
to this auroral camera. (1) Imaging optics is preferred. (2) At apogee, the field-of-view mapped on the ionosphere is wider
than 400 x 400 km, which is about 6 times greater than that of Reimei. (3) Spatial resolution is better than 1 km/pixel to obtainfine-scale aurora. (4) Time resolution is higher than 1 frame/sec to obtain time variation of aurora. (3) It is preferred that thecamera measures auroral emission in the nightside hemisphere under sunlit conditions.
To satisfy the requirements, we carried out the conceptual design of auroral camera as follows, assuming that the satellite isthree axis stabilized and its apogee is 3000 km. The target is auroral N2 1P emission at 670 nm and/or O2 A-band emission at
762 nm. The objective lens is f=100mm (F1.5), and the preferred detector is 1k x 1k EMCCD of which pixel size is 13 x 13 um.
Then, the field-of-view is 7.6 deg, which enable us to cover 400 x 400 km and 200 x 200 km with spatial resolution of 2 km/binand 1km/bin (assuming 5-pix binning) viewed from altitudes of 3000 km and 1500 km, respectively. In the case of 10 frame/sec
sampling and the EM gain 50, we obtain the S/N of 50 for 1kR auroral intensity and the data rate is 4.5 Mbps (assuming losslessdata compression rate of 0.7). We also discuss the requirement for auroral camera measurement under sunlit conditions using a
dipole or IRGF magnetic field model. We find that the satellite exists in the shadow of the Earth at altitude of 3000 km only inthe limited period in the winter hemisphere in addition to that the magnetic pole tilts toward the anti-sunward direction. Thus,
we suppose that we should take auroral image under the sunlit conditions using a baffle prior to the objective lens to reduce thestrong scatter light.

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PCG31-07

Room:202

Time:May 27 17:00-17:15

Solar System Explorations using DESTINY: the Demonstration and Experiment of SpaceTechnology for Interplaneta
IWATA, Takahiro1∗ ; KAWAKATSU, Yasuhiro1 ; MURAKAMI, Go1 ; EZOE, Yuichiro2 ; KAMEDA, Shingo3 ;KEIKA, Kunihiro4 ; ARAI, Tomoko5 ; MATSUURA, Shuji1 ; SAIKI, Takanao1 ; IMAMURA, Takeshi1 ;OGOHARA, Kazunori6
1
5

Institute of Space and Astronautical Science, JAXA, 2 Tokyo Metropolitan Universit, 3 Rikkyo University, 4 Nagoya University,
Chiba Institute of Technology, 6 University of Shiga Prefecture

Demonstration and Experiment of Space Technology for Interplanetary Voyage (DESTINY), which is a candidate missionof Epsilon Launch Vehicle, aims to demonstrate new technologies of high energy orbit insertion, large scale ion engine, ultra
light-mass solar panel, etc. for low-cost deep space mission. It also plans to observe using scientific instruments with the massof up to 10 kg during transfer and Halo orbit of sun to earth Lagrangian point L1 or L2.
Potential scientific objects include in-situ observation and remote sensing from L1 or L2 are, such as, plasma and energetic
particles around the plasma sheet of terrestrial magnetosphere. X-ray Telescope will make imaging of the solar wind charge
exchange (SWCX) with a full coverage from the distance of the Moon and the first full imaging for the magneto-sheath, cusp,
and magnetopause. Ultraviolet Telescope with 10 cm diameter will simultaneously observe the Lyman Alpha emission from thegeocorona. Neutral and Ion Camera will provide a side-view of the dynamical magnetosphere. It would be able to provide thefirst composite movies of how the terrestrial global magnetosphere changes in the solar wind. DESTINY is considered to be
useful for the pilot observations for future infrared, gamma-ray, and cosmic-ray space astronomical telescope. It is probable toobserve and monitor Near Earth Objects (NEO), inter-planetary and inter-stellar dust. Dust Analyzer and High Vision Camera
will provide physical parameters, such as the size and density, and chemical features, such as the metallic and organic compositionof the interstellar dust to elucidate the original material of the solar system and the life. These instruments would observe oneof the most unusual asteroids 3200 Phaethon which has dust tails. High Vision Camera and Thermal Infrared Imager would also
observe the impact flash of the Moon.
Applied missions of DESTINY will be able to go to deep space with higher mass of payloads. Using the Epsilon Launch
Vehicle, it will convey instruments of up to 50 kg to the space between Venus and Mars. Ultraviolet Telescope with the larger
size will observe the absorption lines from the extra-solar planets such as the hot Jupiter and the super earth. Infrared Telescope
settled on the orbit of outside the ecliptic plane will observe the cosmic background radiation. DESTINY launched by the
improved launch vehicle with the power of M-V rocket will carry payloads of up to 200 kg into the orbit of Venus and Mars.
In this phase, climate observations of Venus using two orbiter, and dust-transport mechanism observation of Mars with the
combination of Martian airplane and stationary satellite will be realized.
We will present the possible instruments and model missions for solar system sciences and space astronomy in the DESTINY
series.

Keywords: Epsilon Rocket, DESTINY, solar system exploration, deep space, Lagrangian point

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PCG31-08

Room:202

Time:May 27 17:15-17:30

Super constellation of micro-satellites as a new platform for space investigations
TAKAHASHI, Yukihiro1∗
1

Hokkaido University

It is expected that micro-satellites with a weight less than 100 kg will play important roles in space development in the very
near future due to extreme low cost and the rapid down-sizing. Adding to Surrey Satellite Technology Ltd., a venture companyof Surrey University in UK and one of the pioneers of microsatellite, not a few institutes or companies started entering theinternational race of micro-satellite development. Micro-satellite had been considered as an educational or experimental tool, but
it is not any more at present. Google bought US company, Skybox Imaging, which may launch several tens of, even hundreds of
100 kg-class micro-satellites in the near future for commercial services as a part of Google businesses. Recently, with telescopic
camera on board RISING-2, our second 50 kg-class satellite, we succeeded in acquiring 10-m resolution spectral images withliquid crystal filter, which is the best performance in the world among all kinds of satellites. However, no standardized satellite
BUS or scientific sensors exist in the world. One of the fascinating ideas to realize super multipoint measurement for space
weather monitoring might be installing a standardized scientific plasma sensor package at every micro-satellite as a part of the
BUS instruments. In the near future we may have an opportunity to realize the super constellation with more than several tens of
micro-satellites, organizing international community. Here we would like to discuss how to implement our conception
Keywords: micro-satellite, micro-satellite

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PCG31-09

Room:202

Time:May 27 17:30-17:45

Development of TOF-MS for in-situ K-Ar dating
OISHI, Takahiro1∗ ; SAITO, Yoshifumi2 ; YOKOTA, Shoichiro2 ; KASAHARA, Satoshi2 ; SAITO, Naoaki3 ;FUJIWARA, Yukio3 ; CHO, Yuichiro4 ; MIURA, Yayoi N.5 ; KAMEDA, Shingo4 ; SUGITA, Seiji1
1

Department of Earth and Planetary Science, University of Tokyo, 2 Institute of Space and Astronautical Science, Japan Aerospace
Exploration Agency, 3 National Institute of Advanced Industrial Science and Technology, 4 Department of Physics, Rikkyo University, 5 Earthquake Research Institute, University of Tokyo
In-situ age determination of planetary surface is quite important in understanding the evolution of planets. We are now developing a new instrument for in-situ Potassium-Argon (K-Ar) dating. The K-Ar dating is a radiometric dating method based on themeasurement of 40 Ar that is produced from the radioactive decay of 40 K. This instrument is the combination of laser-induced
breakdown spectroscopy (LIBS) and time-of-flight mass spectrometer (TOF-MS). K is measured using LIBS and Ar is measured
using TOF-MS. In this presentation, we report the current development status of the TOF-MS.
In order to install the instrument on a rover, it is necessary to design the TOF-MS as small as possible due to the severe
restrictions on the mass and power. To increase mass resolution while keeping the size of TOF-MS small, we have adopted adual-stage reflectron that has two-stage reflector with two different electric field intensity. We have analytically optimized thesize and electric field of the reflectron for achieving highest possible mass resolution. We have confirmed that the mass resolutionof the designed reflectron is high enough for K-Ar dating.
We also need to measure a small amount of 36 Ar for the Ar isotope measurement. We have found that the ion detection rateshould be more than 10 percent and the repetition frequency of the ion pulse acceleration should be a few kHz in order to keep
good counting statistics estimating from the amount of the ions generated by LIBS. To improve the efficiency of ion detection,
we simultaneously accelerated the ions within a finite area. We have confirmed that ion detection rate is more than 10 percent by
numerical simulation. Furthermore, for improving the pulse repetition frequency, we have designed the drift tube to be negatively
biased. Since the ion pulse acceleration voltage can be reduced, it is possible to increase the pulse repetition frequency to a few
kHz.
Keywords: TOF-MS, K-Ar dating, Planetary Explora

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PCG31-10

Room:202

Time:May 28 14:15-14:30

Space-borne observation of the ionosphere, thermosphere and the mesosphere
SAITO, Akinori1∗
1

Kyoto University

A micro satellite for imaging of the ionosphere-thermosphere-mesosphere-plasmasphere is being designed in aiming to belaunched in the low-earth orbit. This new observation is expected to clarify the upper atmospheric processes that have been
partially found by the ground-based techniques and the ISS-IMAP missions from the international space station. The new satellite
can observe the Earth’s upper atmosphere with a wide field of view that cannot be observed from ground-based instruments. Maintargets of the observation are: (1) generation, evolution and decay mechanisms of mesoscale structures in the mesosphere and theionosphere, (2) longitudinal and regional characteristics of the atmospheric gravity waves and tidal waves in the mesosphere, (3)disturbances of the thermosphere associated with the geomagnetic storms, (4) electron density distribution in the plasmasphereand its effect on GPS radio waves, (5) the ionospheric effect on the radio waves and development of the correction technique.
Coordinated study among the satellite, ground-based instruments and numerical models is expected to expand our knowledge ofthe mesosphere, thermosphere, ionosphere and plasmasphere from the equatorial to the polar regions. The coupling mechanisms
among high-, mid-, and low latitude regions, and between lower and upper atmosphere will be elucidated by this space-borne
observation.
Keywords: Ionosphere, Mesosphere, Thermosphere, Plasmasphere, space-borne imaging observation

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PCG31-11

Room:202

Time:May 28 14:30-14:45

Development of geocoronal hydrogen Lyman Alpha Imaging CAmera (LAICA) and observational results
IKEZAWA, Shota1∗ ; KAMEDA, Shingo1 ; SATO, Masaki1 ; KUWABARA, Masaki2 ; YOSHIKAWA, Ichiro2 ;TAGUCHI, Makoto1
1

Rikkyo University, 2 University of Tokyo, 3 JAXA

Exospheric hydrogen atoms resonantly scatter the solar ultraviolet radiation, causing an ultraviolet glow called geocorona. Previous research revealed that the geocorona extends to an altitude of about 20RE. The hydrogen Lyman alpha radiation (121.567nm) is the brightest emission of the UV glow.
Bailey and Grantman (2011, 2013) reported that the geocorona has an asymmetric spatial distribution and the total numberof hydrogen atoms increases abruptly (from 6% to 17%) during geomagnetic storms. These observations of the geocorona havemainly been performed using earth orbiters. Therefore, features of the geocorona, such as geocoronal distribution and variationin the number of hydrogen atoms during geomagnetic storms at high altitude are still unclear. In addition, only a few satellites
have observed the geocorona from deep space and, among them, only Apollo16 had a 2D imager. However, its FOV was 10RE
and was not wide enough to image the whole geocorona.
In this study, we developed a UV camera called LAICA (Lyman Alpha Imaging CAmera) for imaging the geocorona fromdeep space. We started developing the LAICA in October 2013. LAICA has a spherical Cassegrain telescope, a bandpass filter, and a detector (a micro channel plate and a resistive anode encoder). The detector is a copy of PHEBUS/FUV on board
the Bepicolombo/MPO satellite. We designed and manufactured the LAICA optical system. Furthermore, we established thegluing method to attach the primary/secondary mirrors and the bandpass filter to the aluminum body. Finally, we completed thedevelopment of LAICA in July 2014. LAICA was then installed in the very small deep space explorer PROCYON, which waslaunched in December 2014. In this presentation, we will describe the details of the LAICA instrument and report our initial
results.
Keywords: geocorona, Lyman alpha line, earth’s atmosphere, space telescope

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PCG31-12

Room:202

Time:May 28 14:45-15:00

Measurement of ionosphere by microsatellite ”GAIA-I” and development of the electron
density and temperature probe: EDTPMIYAZAKI, Takahiro1∗ ; JOSAPHAT TETUKO, Sri sumantyo1 ; ABE, Takumi2 ; NAKAZONO, Tomoyuki3 ;OYAMA, Koichiro4 ; KODAMA, Tetsuya2
1

Chiba University,Japan, 2 Japan Space Exploration Agency,Japan, 3 Advanced Engineering ServicesCo.,Ltd.,Japan, 4 Kyushu
University,Japan

Chiba University plans to hold orbital experiment by using a microsatellite named GAIA-I. The GAIA-I could investigate
relationship between diastrophism and ionospheric phenomenon to seize precursors of earthquake. Many ground based observations show that ionosphere is modified before large earthquakes. The mechanism of the ionosphere modification is still not
known. Recently, ionosphere observation by small and micro satellites has been proposed in order to study the mechanism of
the ionosphere modification. However, conventional ionosphere measurement has some problems in small and micro satellites.
In the case of Langmuir Probe, one problem is that satellite potential changes easily when sweeping voltage which is applied toprobe and second problem is that the measurement is influence by the electrode contamination. We discuss here a new sensor
to observe an electron density and temperature at the same time with one simple low cost, low power consumption and low data
rate instrument. This sensor is called Electron Density and Temperature Probe (EDTP).
EDTP has a probe that is formed by two semicircular plate shapes. When a sinusoidal voltage whose frequency is lower thanion plasma frequency is applied to an electrode, the floating potential shifts to the negative potential. The electron temperature
can be calculated from the ratio of the two floating potential shifts which are caused by applying two successive signal of amplitude a and 2a . This principle to measure electron temperature is applied the instrument was developed in 1970, which is named
Electron Temperature Probe (ETP).
In a high frequency region, plasma impedance is more dominant and the amplitude of sinusoidal signal which is applied between electrode and sheath edge is controlled by the combination of sheath impedance and plasma impedance. Based on thisprinciple, we added one more function of ETP to measure electron density as well by replacing low frequency oscillator which
was used for ETP to sweep frequency generator.
We tested ETDP experiment that compared ETDP with Langmuir Probe and Impedance Probe by using space chamber. Our
experiment has revealed that EDTP is better than conventional ionosphere measurement.
Keywords: Ionosphere, electron density and temperature, microsatellite

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PCG31-13

Room:202

Time:May 28 15:00-15:15

Submillimeter limb sounder for stratospheric and mesospheric temperature, wind, andchemical species
OCHIAI, Satoshi1∗ ; UZAWA, Yoshinori1 ; NISHIBORI, Toshiyuki2 ; SUZUKI, Makoto2 ; SHIOTANI, Masato3
1

National Institute of Information and Communications Technology, 2 Japan Aerospace Exploration Agency, 3 Kyoto University

Submillimeter-wave limb sounder has a potential for measurement of temperature, wind, and chemical species, such as H2 O
and O3 , over the wide altitude range of the Earth’s atmosphere, ie. from the lower stratosphere to the lower thermosphere. The
submillimeter sounder has receivers in a couple of frequency bands to observe emission lines of several chemical species and O2 .
Each band will be detected with high-resolution spectrometer on the back end of the sounder. Supposed mission in the working
group of our project consists of highly sensitive receivers of two or four frequency band and spectrometers with a bandwidth of
2 or 4 GHz and a resolution of around 1 MHz. Its specifications will be determined in the working group in next 3 years. In thispaper, we will report the present status of our study toward the design of SMILES-2, which will be an advanced version of thesuccessful mission, JEM/SMILES, deployed on the international space station (ISS) from 2009 to 2010.
The sensitivity of submillimeter receiver using superconducting technology shows one order better than semiconductor devices
operated in ambient temperature. The sensitivity restricts the range of the variation of observable molecules and the altitude
range. The observation of the higher atmosphere above the mesosphere is especially limited by the sensitivity, because theemission from the atmosphere is comparatively weak while the noise in the received signal, that is dominated by the receivernoise, is constant in spite of disappearing of background emission. Superconducting receiver is preferable for the observationin such upper atmosphere. JEM/SMILES adopted superconducting mixer at 625 and 650 GHz, and successfully demonstrated
excellent observation of ozone and chlorine compounds and so on. The SSB system noise temperature of the JEM/SMILES
receiver was 297 K, which is less than a tenth of that of Schottky receiver of those days. The frustration of JEM/SMILES users
was that the mission observed no oxgen line and no atmospheric tracer. The limitation of JEM/SMILES bandwidth had comefrom safe design avoiding electromagnetic interference in ISS. The thermal design of the JEM/SMILES cryo system had been
also safe so that only two receivers were loaded in the cryo system. In SMILES-2, wider range of frequency band will be used
in instrument of smaller weight. It will realized by utilizing wide-band intermediate frequency and reducing optics system. The
antenna of SMILES-2 is steerable in elevation angle. The altitude resolution of the limb observation is targeted to around 2 km.
The azimuthal direction of the antenna is under discussion. The calibration load in JEM/SMILES was successful and contributed
to measure precise spectral data, so that the load will be applied to multi frequency receiver.
The SMILES-2 mission will have a weight of about 200 kg. We estimate it is possible to reduce the weight of the system fromthat of JEM/SMILES, that is 476 kg. Besides the superconducting receiver, Schottky receivers will be installed in SMILES-2 tomake the system reliable because expected lifetime of cryocooler is 3 years and we wish to prolong the mission life. An only
Schottky receiver mission is also planned for a quick mission.
Keywords: middle atmosphere, limb observation, submillimeter wave, instrument development, future mission, SMILES

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PCG31-14

Room:202

Time:May 28 15:15-15:30

Sensitivity study of chemical species for SMILES-2
MANAGO, Naohiro1∗ ; SUZUKI, Makoto2 ; OZEKI, Hiroyuki3 ; BARON, Philippe4 ; OCHIAI, Satoshi4
1Center for Environmental Remote Sensing, Chiba U., 2 ISAS, 3 Toho U., 4 National Institute of Information and Communications
Technology
Superconducting Submillimeter-Wave Limb-emission Sounder (SMILES) was the first instrument to use 4K cooled SIS(Superconductor-Insulator-Superconductor) detection system for the observation of the atmosphere in the frequency regions 625
GHz (Bands A and B) and 650 GHz (Band C) [1]. It has demonstrated its high sensitivity (System Temperature, Tsys ˜250K) for
measuring stratospheric and mesospheric species, O3, HCl, ClO, HO2, HOCl, BrO, and O3 isotopes from Oct. 12, 2009 to Apr.
21, 2010 [2-5]. Since SMILES operation has terminated after only 6 months operation due to failure of sub-mm local oscillator(and later 4K cooler system), there exist strong scientific demand to develop successor of SMILES, the SMILES-2, which has
optimized and enhanced frequency coverage to observe: (a) BrO and HOCl without interferences of stronger emission lines, (b)N2O, H2O, NO2, and CH3Cl not covered by the SMILES frequency regions, and (c) O2 line to measure temperature. This paper
discusses possible SMILES-2 band selection considering limited instrument resources (number of SIS mixers and sub-mm local
oscillator) and scientific requirements.
SMILES L2 system used strong O3 and HCl lines to retrieve temperature, which has sensitivity only up to 40-50 km. Temperature should be observed by SMILES-2 itself up to (or above) 100 km with a sensitivity of 1% (2-3K), since the temperature is
the primary physical parameter to determine the dynamics and chemistry of the atmosphere and there is no global meteorological
data set which is reliable above 60 km. SMILES-2 should have observation capability of H2O and N2O better than 5% precision,
which are not observed by SMILES and are important tracers in the upper atmosphere. These are major sources of HOx andNOx. SMILES-2 should improve HOCl and BrO sensitivity by properly selecting observation frequency. SMILES BrO and
HOCl observations have suffered severe interference from the near-by stronger lines. SMILES-2 should have original SMILES
frequency coverage, and if possible it should add observation of other species retrieved in the Aura/MLS and Odin/SMR.
Instrument Altitude range: 10-120 km, 2.5 km vertical sampling. Frequency sampling: 4 GHz bandwidth, 500 kHz samplinginterval, 1.3 MHz Gaussian (FWHM). Tsys = 150 K, Integration time <0.48 s.
(Band 1) 485-489 GHz: T, Wind, O2, H2O, O3, HO2, HNO3
(Band 2) 523-527 GHz: O3, 17OOO, 18OOO, O17OO, O18OO, BrO, NO2, H2CO, N2O, HO2(Band 3) 612-616 GHz: HOCl, O3, HO2(Band 4) 623-627 GHz: SMILES Bands A+B extended, O3, HCl, BrO, HNO3, HO2, N2O, HOCl, CH3CN, CH3Cl(Band 5) 648-652 GHz: SMILES Band C extended, O3, 17OOO, O17OO, 18OOO, ClO, HO2, BrO, NO[1] K. Kikuchi et al., Overview and early results of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES),
J. Geophys. Res., 115, no. D23306, pp. 1-12, 2010.
[2] K. Imai et al., Validation of ozone data from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES),
J. Geophys. Res., 118 (11), pp. 5750-5769, 2013.
[3] T. Sakazaki et al., Diurnal Ozone Variations in the Stratosphere Revealed in Observations From the Superconducting
Submillimeter-Wave Limb-Emission Sounder (SMILES) on Board the International Space Station (ISS), J. Geophys. Res., 118(7), pp. 2991-3006, 2013.
[4] A. K. Smith et al., Satellite observations of ozone in the upper mesosphere, J. Geophys. Res., 118 (11), pp. 5803-5821,
2013.
[5] R. A. Stachnik et al., Stratospheric BrO abundance measured by a balloon-borne submillimeterwave radiometer, Atmos.
Chem. Phys., 13, pp. 3307 - 3319, 2013.

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PCG31-14

Room:202

Time:May 28 15:15-15:30

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PCG31-15

Room:202

Time:May 28 15:30-15:45

Mesospheric wind observation from Sub-millimeter limb sounding: Results from SMILES
and simulation study for SMILES-2
BARON, Philippe1∗ ; MANAGO, Naohiro2 ; OZEKI, Hiroyuki3 ; UZAWA, Yoshinori1 ; OCHIAI, Satoshi1 ;SUZUKI, Makoto4
1

NICT, 2 Chiba University, 3 Toho University, 4 Institute for Space and Astronautical Sciences, Japan Aerospace Exploration
AgencyWind observations in the middle atmosphere, i.e. stratosphere and mesosphere are sparse [1]. Observations have been obtained from ground-based active sensors (radar and lidar), and recently from passive infra-red and microwave spectrometers.
Satellite observations were successfully conducted with instruments on-board the UARS and TIMED satellites but they mainly
cover the mesosphere. Mesospheric winds have also been retrieved from AURA/MLS using the O2 line at 118 GHz. It was thefirst demonstration that good quality winds can be provided by a microwave limb sounder. More recently winds were measured
between 30 and 80 km (with a theoretical lower limit of 20 km), by the Superconducting Submillimeter Wave Limb Emission
Sounder (SMILES) onboard the Japanese Experiment Module on the International Space Station. The advantage of SMILES
was its low measurement noise, about 5 to 10 times lower than concurrent systems such as Odin/SMR and AURA/MLS [2].
Such noise level was obtained with the use of two 4-K cooled SIS mixers. However, the instrument was not designed for windobservations and suffered from serious limitations due to the choice of the spectrometers (type, bandwidth, resolution) and of
the spectral lines. Sensitivity studies [3,4] have shown that with a careful selection of these parameters, the line of sight windvelocity can be retrieved between 40 ̶ 90 km with a precision of 2 m/s and a vertical resolution of about 5 km, even without theuse of a SIS mixer.
Wind has been selected as one of the products for the study of the successor of JEM/SMILES, namely SMILES-2, whose themain target is the study of the dynamics and chemistry in the mesosphere. In this presentation we summarize the results obtained
from JEM/SMILES and discuss the SMILES-2 potential for wind measurements.
References:[1] P. Baron, D. P. Murtagh, J. Urban, H. Sagawa, S. Ochiai, Y. Kasai, K. Kikuchi, F. Khosrawi, H. Kornich, S. Mizobuchi, K.
Sagi, and M. Yasui. Observation of horizontal winds in the middle-atmosphere between 30S and 55N during the northern winter2009 ̶ 2010. ACP, 13(13), 2013.
[2] K. Kikuchi, Nishibori, T., Ochiai, S., Ozeki, H., Irimajiri, Y., Kasai, Y., Koike, M., Manabe, T., Mizukoshi, K., Murayama,Y., Nagahama, T., Sano, T., Sato, R., Seta, M., Takahashi, C., Takayanagi, M., Masuko, H., Inatani, J., Suzuki, M., Shiotani,
M. Overview and Early Results of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES), JGR Atmospheres, 2010
[3] P. Baron, D.P. Murtagh, J. Urban, H. Sagawa, P. Eriksson, S. Ochiai, Definition of an uncooled Sub-Millimeter/THz Limb
sounder for measuring middle Atmospheric winds., Proc. In ESA Living Planet Symposium, 2013.
[4] N. Manago, H. Ozeki, and M. Suzuki. Band selection study for the SMILES-2, Proc. In 28 Taikiken symposium, 2014
Keywords: mesosphere, wind, SMILES, limb, microwave

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PCG31-16

Room:202

Time:May 28 15:45-16:00

Initial performance verification of Atmospheric Neutral Analyzer for in-situ observationsof planetary atmospheres
ARIMI, Koki1∗ ; SHIMOYAMA, Manabu1 ; ITO, Fumihiro1 ; HIRAHARA, Masafumi1
1

Solar-Terrestrial Environment Laboratory, Nagoya University

The dynamics in the neutral upper atmosphere of the Earth and the other planets affect the environment of their ionospheres andthe thermospheres. In-situ observations of the neutral atmospheres utilizing spacecraft are needed for understanding atmosphericcirculations, heating, and dissipation. Neutral Mass Spectrometers for the terrestrial and planetary explorations have not had acapability to directly observe two-dimensional particle velocity distributions in the past. Therefore, detailed information on theinteraction of the upper atmosphere with the solar wind and the dynamics of neutral particles have not been obtained so far.
We are newly developing a Bennett-type radio-frequency mass spectrometer, which is called Atmospheric Neutral Analyzer(ANA). The ANA is capable of observing 2-D velocity distributions, from which density, wind velocity and temperature arederived, for each component of neutral species. The ANA consists mainly of five sections: an entrance slit, an ionization section
utilizing electron gun, a pre-acceleration section, a Radio Frequency (RF) stage for mass spectrometry, and a detection section
which obtains 2-D velocity distributions in combination of MCP with 2-D position-sensitive device. We now concentrate on thedevelopment of the whole ion mass spectrometer after the ionization section.
In addition to the numerical design of the structure and the performance of the mass spectrometer by using SIMION 8.1, wenewly had experiments to investigate the characteristics of the engineering model of the ANA except for the ionization section.
We, here, used the suprathermal ion beamline of Ar+ and N2 + . For the calibration, we set the ANA in a vacuum chamber, andirradiated the ions with energies of several to a few tens of eV, in order to investigate its response. Because the spacecraft velocity
is assumed to be 8 km/s, the energy of the irradiated ions must correspond to it. The energies of the Ar+ and N2 + of 8 km/s
are 13.3 and 9.3 eV/charge, respectively. We irradiated the Ar+ and N2 + beams of 8 km/s, but the beam ions were not detectedin the detection section. Instead, particles whose energies were approximately 17 eV (Ar+ ) and 13 eV (N2 + ) were detected
when the voltages of the ANA electrodes were of reference values for the 8 km/s cases of each species. We are now considering
the possibility of fabrication errors in ANA. Besides, the irradiated Ar+ whose energy was 17 eV was not detected when theparameter of the ANA electrodes were of reference values for the 13 eV cases of the N2 + . And vice versa.
In the presentation, we will show the overall design of the ANA regarding the mass spectrometry and the characteristics
investigated by the simulation and the beamline experiments.
Keywords: Planetary atmosphere, In-situ observation, Neutral mass spectrometer, Equipment development

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PCG31-17

Room:202

Time:May 28 16:15-16:30

The design of the suprathermal ion mass spectrometer (STIMS)ISHIGURO, Keisuke1∗ ; HIRAHARA, Masafumi1
1

STEL, Nagoya Univ.

Ion escape processes are critical issues to solve atmospheric evolution of non-magnetized planets, e.g., Venus and Mars. Many
studies about the ion escape have been conducted by both observational and theoretical methods. There is, however, a problem
that qualities of in-situ observations have not been sufficient to identify the detailed suprathermal plasma dynamics, especiallyabout molecular ions, around the non-magnetized planetary ionospheres. A suprathermal ion mass spectrometer (STIMS) has
been designed for future in-situ observations of three dimensional velocity distributions for suprathermal ions around the planetary atmospheres.
The STIMS consists of (a.) an energy analyzer and (b.) a mass analyzer. A field of view of the STIMS is about 4 pi sr per ahalf spin of spin-stabilized spacecraft. A target energy range is from 0.1 to 300 eV, which corresponds to suprathermal energies,
and a mass range is from 1 to 50 amu. An energy resolution, 4E/E, is less than 5%, and a mass resolution, M/4M, is over 10.
(a.) An energy analysis of the STIMS is carried out in a top-hat type electrostatic analyzer, which deflects incident ions by 90
degrees and leads them to an entrance of the mass analyzer. Only ions that fly along a center radius of spherical electrodes areable to get to the mass analyzer.
(b.) The mass analyzer of the STIMS is mainly made up of a pre-acceleration section and a magnet section. The magnet
section, which has a cylindrically symmetric structure, is divided into sixteen regions by permanent sector magnets. Firstly, inthe pre-acceleration section, ions which got through the energy analyzer are accelerated or decelerated by an acceleration voltage
E eV, whose magnitudes depend on mass number of the ions M amu. Secondly, the accelerated/decelerated ions experience
Lorentz force in the magnet section, and reach a micro-channel plate (MCP), with semicircular trajectories. By sweeping magnitudes of the acceleration voltage E , only ions that conserve square root of product of their masses and kinetic energies, i.e., √ME , are able to reach the MCP.
As for observations of molecular ions, magnet type mass spectrometers have a great advantage that it is possible to detect themolecular ions without dissociations. However, this type of spectrometer has several disadvantages; (1) it is difficult to discriminate between noise signals and ion signals at the MCP because this type of spectrometer does not take signal coincidences; (2)this type of mass spectrometer tends to be heavier than other types of spectrometers due to installing magnets; (3) magnetic fieldof the magnets might cause undesirable effect on other observation instruments on spacecraft.
In this presentation, we will introduce design concepts and specifications of the STIMS.

Keywords: ion mass spectrometer, suprathermal ion, non-magnetized planet, planetary ionosphere

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PCG31-18

Room:202

Time:May 28 16:30-16:45

Space-terrestrial couplings and polar ionosphere/thermosphere dynamics studied by formation flight of compact satellites
HIRAHARA, Masafumi1∗ ; SAITO, Yoshifumi2 ; ASAMURA, Kazushi2 ; SAKANOI, Takeshi3 ;KOJIMA, Hirotsugu4 ; MIYOSHI, Yoshizumi1 ; OYAMA, Shin-ichiro1
1

Solar-Terrestrial Environment Laboratory, Nagoya University, 2 Institute of Space and Astronautical Science, Japan Aerospace
Exploration Agency, 3 The Planetary Plasma and Atmospheric Research Center, Tohoku University, 4 Research Institute for Sustainable Humanosphere, Kyoto University
We have been discussing a possibility and feasibility of the future space exploration mission for studying the space-terrestrial
couplings based on the space plasma dynamics. In this future mission, we are planning to elucidate the universal particle acceleration/heating and transport mechanisms by using the in-situ and remote-sensing observation techniques with a formation flightof multiple compact satellites. These plasma dynamics are caused mainly by the terrestrial ionosphere-magnetosphere coupling
processes and also affect both mangetospheric plasma dynamics and upper atmospheric (ionospheric and thermospheric) phenomena in the Earth’s polar regions. In past, our Reimei satellite, the first Japanese microsatellite focusing on the exploration of
the fine-scale auroral dynamics, was launched in August, 2005. Reimei successfully obtained the in-situ observational data forthe space plasmas but the imaging camera data for the auroras, the airglows, and the sprites. These Reimei results have been leading to several new satellite mission proposals in the world. We are now organizing a highly plausible mission based on our own
experimental experiences obtained from Reimei and our data analysis achievements, for instance, in the ISAS Akebono mission
and the NASA FAST mission. It is undoubtedly evident that highly accurate measurements of magnetic/electric fields and plasma
waves should be realized in this future satellite missions in addition to the monochromatic auroral imaging camera with hightime/spatial resolutions and the energetic and suprathermal electron/ion analyzers with a high-time resolution. Thermal plasma
instruments are also important for measuring the plasma circumstances. It should be noticed that the neutral particle instruments,
which are now under development and modification in Japan, would significantly contribute to the quantitative researches of thepolar ionospheric and thermospheric dynamics. Toward the realization of the new space exploration mission, we are making
intensive efforts for defining the scientific mission strategy and the specifications of the science instruments. In the future mission planning, we are now considering the following features. 1: Changeable formation flight with multiple compact satellites,
whose weights are roughly 100 kg, is essential for simultaneous multipoint observations of fine-scale auroral phenomena. 2: The
precise three axial attitude control system should be applied for realizing the high-quality 2-D imaging of auroral emissions andthe simultaneous measurements of the pitch-angle distributions of the auroral particles with top-hat type energy analyzers. 3: It
is crucial to capture the ram direction of the satellite with the attitude control in order to measure the shifted velocity distributionsof the core ions. 4: The electric/magnetic field instruments and the plasma wave instruments should be installed on the satellites
for the integrated observations. Particularly, it is one of the most prominent features of this mission to perform wave-particle
interaction analyses based on these comprehensive and integrated measurements of the plasma particles and waves, and the fields.
5: Neutral particle instruments for the velocity distribution measurements would make essential contributions from the farsighted
viewpoint in the upper atmospheric dynamics beyond the space plasma regimes. 6: The sun-synchronous orbit at relatively low
altitudes would be desirable both for bringing the observational advantages. In this presentation, we introduce the multi-sided
scientific importance and several types of our exploration mission specification.
Keywords: space plasma, particle acceleration, space-terrestrial coupling, wave-particle interaction, integrated observation, formation flight

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PCG31-19

Room:202

Time:May 28 16:45-17:00

Study on miniaturization and accelertion of onboard digital signal processing module forplasma wave instruments
KASAHARA, Yoshiya1∗ ; MATSUI, Hiroki1 ; GOTO, Yoshitaka1
1

Kanazawa University

Measuring plasma wave is one of important clues to understand space plasma physics, and it is necessary to implement
intelligent signal data processing techniques into the plasma wave instruments. It is necessary to reduce the weight and sizeof the instruments to meet the requirements of future missions such as flying formation satellites and planetary exploration
spacecraft. In the present study, we developed a FPGA board, which enables us to develop arbitrary digital signal processing
applicable for the future missions.
Our FPGA board is designed to evaluate the performance of signal processing module, which is especially used for various
kinds of real-time signal processing. The board consists of one CPU connected with a USB port, and two sets of FPGA and
DDR2. One set of FPGA and DDR2 is equipped for storing input signal data and sending them to another one, which is used forthe evaluation of real-time data processing module and storage of output data. The input and output data stored in the DDRs canbe accessed from the onboard CPU, and we can easily control the CPU using Tera Term through a USB port. We also developed
a general purpose module for evaluation of a proposed signal processing method. By using this module, a developer can integrate
his/her own signal processing module on the FPGA board without any complicated wiring work for the peripheral circuits andevaluate the performance of his/her own module. Finally we implemented a sub-band compression module developed for realtime data compression of waveform measured by the plasma wave instruments. It was demonstrated that the designed module iscompact and fast enough to realize real-time processing for 6 channels of waveform data.
Keywords: Waveform capture, Verilog-HDL, Plasma wave instruments, Signal processing

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PCG31-20

Room:202

Time:May 28 17:00-17:15

Miniaturization of plasma wave instruments and its perspective towards future space missions
KOJIMA, Hirotsugu1∗ ; OZAKI, Mitsunori2 ; YAGITANI, Satoshi2 ; ZUSHI, Takahiro1 ; ONISHI, Keisuke1 ;KASAHARA, Yoshiya2 ; SAITO, Yoshifumi3
1

Kyoto University, 2 Kanazawa University, 3 ISAS, JAXA

The miniaturization of onboard instruments is essential in executing space plasma observations using microsatellites. In particular, conventional plasma wave instruments have a large size of analogue circuits such as low noise amplifiers and various
types of filters. In addition, onboard digital processing such as data compression and FFT calculation requires large budgets ofmass and power in using CPU. However, the capability of the onboard CPU does not support the real time onboard processingof plasma wave observation data. We need to convert the processing using software into the processing using hardware such as
FPGA and digital ASIC.
We have been attempting the miniaturization of plasma wave instruments using mixed signal ASIC technology. We havealready succeeded in realizing six channels of waveform capture receiver inside the chip with the size of 5mm times 5mm. We
also realized the preamp chip for magnetic sensors. Furthermore, this ASIC technology leads to the consolidation of the digitalpart and analogue part of plasma wave receivers. This means that the whole plasma wave receiver system will be installed inside
a one chip. In the present paper, we will introduce our attempt of the miniaturization of plasma wave receiver using the ASIC
and show you the perspective using the miniaturized plasma wave receiver.

Keywords: Plasma wave, ASIC

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PCG31-21

Room:202

Time:May 28 17:15-17:30

Small Sensor Probe for Multiple Point Observation of Plasma Waves
ZUSHI, Takahiro1∗ ; KOJIMA, Hirotsugu2 ; ONISHI, Keisuke1 ; OZAKI, Mitsunori3 ; YAGITANI, Satoshi3 ;SHIMIZU, Satoru4
1
3

Kyoto University, Graduate School of Engineering., 2 Kyoto University, Research Institute for Sustainable Humanosphere.,
Kanazawa University, Faculty of Electrical and Computer Engineering., 4 Oki Electric Industry Co., Ltd.

Recently, multi-spacecraft missions for observing space plasma phenomena have become the trend because multiple point observation is essential in overcoming the disadvantage of conventional one point observation. However, multi-spacecraft missions
have a limit to the number of observation point and disposition of spacecraft because of the weight and the size. We propose a
new system for multiple-point observation referred to as the monitor system for space electromagnetic environments (MSEE).
The MSEE consists of small sensor probes that have a plasma wave receiver, a wireless communication module and electromagnetic sensors to measure electromagnetic waves and transfer observation data. The sensor probes are randomly distributed
throughout the target area to observe plasma waves from multiple-point. Observation data are transferred to a central station,such as a satellite or a rocket through wireless communication.
We succeeded in designing and developing the prototype model of the MSEE sensor probe. The sensor probe includes theminiaturized plasma wave receiver, the microcontroller, the wireless communication module, and the battery in the 75 mm cubic
housing. In addition, loop antennas, dipole antennas and actuators that are used for expanding dipole antennas are attachedon the housing. The whole weight of the sensor probe is 692 g, and the total power consumption is 462 mW. We verified thetotal performance for electric field measurements, and we found that analog components had enough characteristics to measureelectric fields, and the A/D conversion and the wireless transmission worked correctly.
Present sensor probe use miniaturized waveform capture (WFC) type of plasma wave receiver realized by Application SpecificIntegrated Circuit (ASIC). Although the waveform receiver can provide phase information of waves, it has disadvantages thatit cannot measure continuously due to the limit of the telemetry capacity. Thus it is desirable to use both types of receivers inplasma wave observation. It requires spectrum type receivers for continuously observation. We proposed new spectrum typeplasma wave receiver that overcome the disadvantage of conventional spectrum type receivers. New spectrum receiver copeswith both high time resolution and high frequency resolution by combining analog circuits and digital signal processing. We
succeeded in developing the analog circuit of the new spectrum receiver using ASIC.
In this presentation, we introduce the detail design and the performance of the prototype model of the sensor probe. We also
introduce the new spectrum type receiver.
Keywords: plasma wave receiver, multiple-point observation, ASIC

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PCG31-22

Room:202

Time:May 28 17:30-17:45

Recent progress in developing search coil magnetometer using ASIC technology toward
micro-satellite experiments
OZAKI, Mitsunori1∗ ; YAGITANI, Satoshi1 ; KOJIMA, Hirotsugu2 ; KOJI, Hiroki1 ; ZUSHI, Takahiro2
1

Kanazawa University, 2 RISH, Kyoto University

Magnetic field components of plasma waves are essential for probing space plasma environments. Search coil magnetometers
are commonly used in satellite experiments and well-adapted to the measurements in the frequency range from a few Hz toseveral tens of kHz. A search coil sensor is installed at the top of a few-meter long mast or boom to reduce a noise contaminationfrom a satellite. Then a preamplifier could be installed inside the satellite due to thermal and radiation conditions in space.
Such a preamplifier separated from a sensor has disadvantages for the signal-to-noise ratio and the system resource. Recently,
application specific integrated circuits (ASICs) are one of key technologies for increasing demands of plasma wave observations
using multiple micro satellites. In order to further reduce mass, volume, and power consumption of analog circuits in typicalplasma wave instruments, we have developed a low noise ASIC preamplifier for search coil magnetometer. The preamplifier
is an important analog component of plasma wave observation to determine the noise equivalent magnetic induction (NEMI).
In this study, a current-sensitive preamplifier for search coil magnetometer was developed and fabricated on a 6-mm2 siliconchip by using a standard 250 nm complementary metal-oxide semiconductor (CMOS) technology. A search coil sensor shows amaximum value of its impedance at the resonance frequency. The NEMI at the resonance frequency is determined by multiplying
the sensor impedance by the current noise of preamplifier. Thus, the ASIC preamplifier using CMOS technology is more suitable
for search coil magnetometer compared to a preamplifier using bipolar junction transistors, because MOS transistors show√thevery low current noise. The NEMI of developed ASIC preamplifier combined with a 100-mm-long search coil is 30 fT/ Hz
at 2 kHz with a power consumption of 15 mW. The radiation hardness assurance of the ASIC preamplifier is at least 100 krad
total ionizing dose, which is equivalent to approximately the total amount for 10 year duration at the geostationary orbit. The
temperature dependence of the gain of the ASIC preamplifier is 0.04 dB/deg C in the worst case. The ASIC preamplifier showing
such sufficient NEMI, low power budget, and environmental tolerance in space can be installed in the close vicinity of the searchcoil sensor located at the top of a mast. Also the ASIC preamplifier can provide large mass saving. As an application, we
have embedded a new ASIC preamplifier for 3-axis loop antennas into a palm-sized sensor probe as a monitor system for spaceelectromagnetic environments. The sensor node includes the ASIC preamplifiers, an ASIC waveform receiver, a CPU, and awireless communication module in the cubic body (8 × 8 × 8 cm).
In this presentation, we will report the present status of our ASIC preamplifier and also introduce some applications using the
ASIC preamplifier for plasma wave observation.

Keywords: Search coil magnetometer, ASIC

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PCG31-23

Room:202

Time:May 28 17:45-18:00

Evaluation of the effective measurement frequency for the digital fluxgate magnetometer
installed in the S520-29 rocket
NOMURA, Reiko1∗ ; MATSUOKA, Ayako1 ; ABE, Takumi1
1

ISAS, JAXA

The digital fluxgate magnetometer (DFG) is newly developed and installed in the S520-29 rocket launched on 17 August
2014. We expand the effective measurement frequency to higher frequencies by performing internal processes in the sensor andoutputting the residual magnetic fields as the telemetry data. This is the new method that can be applied into the future rocket
and satellite missions for higher-accuracy, downsized, and power-saving measurements.
The sun sensor is also installed in the S520-29 rocket and the direction to the sun from the rocket is accurately measured. By
comparing the magnetic field in the direction to the sun observed by DFG to the one calculated by the model (e.g., IGRF), we
investigate the magnetic field offset in the direction of the spin axis caused by DFG or the rocket, and also evaluate the stabilityof DFG measurement during the flight operation. In our presentation, we present how the new-type DFG improved its effective
measurement frequency.

1/1

PCG31-P01

Room:Convention Hall

Time:May 27 18:15-19:30

Potential for seismic investigation of Europa using meteorite impacts
TSUJI, Daisuke1∗ ; TEANBY, Nicholas2
1

Graduate School of Environmental Studies, Nagoya University, Japan, 2 School of Earth Sciences, University of Bristol, UK

Europa, one of the Galilean satellites of Jupiter, has an icy outer shell, beneath which there is probably liquid water in contact
with a rocky core [1]. Europa, may thus provide an example of a sub-surface habitable environment so is an attractive object for
future missions to explore. In fact, the Jupiter Icy Moon Explorer (JUICE) mission has been selected for the L1 launch slot of
ESA’s Cosmic Vision science programme with the aim of launching in 2022 to explore Jupiter and its potentially habitable icy
moons.
In order to improve our understanding of the internal structure, a seismic investigation would provide powerful constraints.
The Apollo seismic experiment detected numerous seismic events on the Moon, and has revolutionized our knowledge of thelunar interior. On Mars, unmanned establishment of the Viking seismometer was carried out despite the fact that it was not able tocapture any detectable events due to the poor coupling to the ground. The deficiency will be addressed by NASA’s 2016 InSight
Mars lander.
In this study, we investigate the detectability of seismic waves on Europa’s surface caused by meteorite impacts. Internal
fracturing and cracking of the icy crust could be the largest source of seismic waves, but in general multiple well-dispersed
seismometers are necessary to locate the seismic source. However, meteorite impact sites could potentially be located using
other methods such as surface imaging. The internal structure could then be estimated using a single seismometer. Recently,
the seismic detectability on Mars using a single seismic station has been studied [2]. Motivated by this work, we estimate thenumber of detectable meteorite impacts per year on Europa by the process mentioned below.
1) We derive a relation between the crater diameter and the impactor’s kinetic energy based on observational data compiled
from impact tests, controlled explosions, and simulations.
2) Impact frequency on Europa is estimated by the distribution of observed crater sizes.
3) The results of 1) and 2) are combined to give the number of meteorite impacts which can be detected per year.
4) Taking the precision of practical seismic instruments into consideration, we discuss if using a single seismic station could
be a reliable way of probing Europa’s interior.
Reference[1] F. Cammarano et al., J. Geophys. Res., 111, E12009 (2006)[2] N. A. Teanby and J. Wookey, PEPI, 186, 70 (2011)

Keywords: Europa, icy satellites, meteorite induced seismicity, planetary exploration

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PCG31-P02

Room:Convention Hall

Time:May 27 18:15-19:30

Development of electric field instrument onboard spacecraft
ISHISAKA, Keigo1∗ ; KOJIMA, Hirotsugu2 ; KASABA, Yasumasa3 ; ABE, Takumi4
1

Toyama Prefectural University, 2 RISH, Kyoto University, 3 Tohoku University, 4 ISAS

Measurements of electric fields are one of key elements for various missions. The detection of electric field is useful to identify
global plasma dynamics and energetic processes in magnetosphere and ionosphere. The concrete examples are as follows.
- Electric field structure associated with the charged particle precipitation- Electric field structure associated with the global motion of the ionosphere- The role of the electric field in the acceleration and heating mechanisms of ions
- Propagation mechanism of the electric field in the auroral ionosphere to the low latitude ionosphere- Electric field structure in the equatorial ionosphere
Many electric field measurements have been carried out in Japan. And the electric field detector onboard sounding rockets andsatellites have been successfully used in the D, E and F regions of the ionosphere and in the magnetosphere.
The double probe technique have been extensively used on sounding rockets in order to measure electric field in the ionosphere.
And the passive double probe technique has been proven to be a reliable technique in the high electron density plasmas of theionosphere. The technique has been extended to the lower density plasmas of the D region of the ionosphere. For electric fieldmeasurement, a wire antenna has been used as a sensitive sensor onboard Japanese sounding rocket. And this antenna will be
used for several spacecraft in the future mission. However, its extension mechanism is complicated and it is difficult for thesounding rocket to extend a wire antenna in the ionosphere. Accordingly new type antennas are developed in order to measure
the electric field by the sounding rocket. Their antennas fulfill the severe requirements to the antenna system, i.e., light mass,
enough stiffness, compact storage, safe extension, and reasonable test efforts. Three antennas were newly developed for theelectric field measurement. These antennas were loaded on three sounding rocket in Japan (S-310-37, S-520-23, S-520-26). And
these new style antennas deployed normally during the flight of a sounding rocket, and succeeded in the electric field observationin the ionosphere.
This paper describes about the basic measurement techniques of the electric field in the ionosphere. In particular it explains
about three new type antennas in detail. Then we show the electric field in the ionosphere measured by the new type antenna
onboard the Japanese sounding rocket.
Keywords: electric field instrument, electric field sensor, antenna, sounding rocket, small satellite

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PCG31-P03

Room:Convention Hall

Time:May 27 18:15-19:30

Developing of a chip for the interface between plasma wave instruments and plasma particle instruments
ONISHI, Keisuke1∗ ; ZUSHI, Takahiro1 ; KOJIMA, Hirotsugu2 ; SAITO, Yoshifumi3
1

Graduate School of Engineering, Kyoto University, 2 Research institute for sustainable humanosphere, Kyoto University, 3 Solar
System Science Division, Institute of Space and Astronautical Science, Japan Aerospace Explora
Since space plasmas are essentially collisionless, kinetic energies of plasma particles are exchanged through the plasma waves.
These interactions among the space plasmas and the plasma waves are called the wave-particle interactions. The wave-particle
interactions are very important in analyzing electromagnetic phenomena occurring in space.
The Wave-Particle Interaction Analyzer (WPIA) is proposed in order to analyze the wave-particle interactions quantitatively
and directly, and it will be installed in the next satellite mission ERG of Japan. The WPIA needs to measure the timing of theeach particles at the same accuracy as the sampling frequency of the plasma wave. In the case of the ERG, the relative time
accuracy is guaranteed by using the time information from the plasma wave instrument. The most precise method is using thesame clock for the particle detection as the sampling clock of the plasma wave. Developing the circuit which interface the particle
observation pulse with the plasma wave instruments removes the complicated procedure of time setting and enables more simply
observation with high accuracy. In this study, we develop the interface circuit which input each pulses derived from the particle
to the plasma wave instrument. The circuit composed of discrete components is large scale because the number of outputs fromthe plasma particle instruments increases according to the number of view divisions. Using the application specific integrated
circuit (ASIC), we design the new dedicated chip which takes signals from the plasma particle instruments to the plasma wave
instruments.
The interface circuit consists of two stages. The pre-stage converts electric charge to voltage, and the post-stage detects thearrival of a plasma particle from the voltage of the pre-stage. We use a voltage follower circuit as the pre-stage and a comparator
circuit as the post-stage. We have designed the pre-stage circuit. The waveform input to the pre-stage circuit is estimated acurrent pulse at the frequency of several GHz. In order to convert current pulse to voltage with small delay and distortion, we
have designed an operational amplifier which is capable of operating at a high speed, and have requested to manufacture a chip.
In the present paper, details of the interface circuit and measurement results of the manufactured chip will be focus on.

Keywords: Wave-particle interaction, Interface, ASIC

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PCG31-P04

Room:Convention Hall

Time:May 27 18:15-19:30

Improvement of dynamic range of ASIC waveform receiver for plasma wave observations
KOJI, Hiroki1∗ ; OZAKI, Mitsunori1 ; YAGITANI, Satoshi1 ; KOJIMA, Hirotsugu2 ; ZUSHI, Takahiro2 ;YOSHIDA, Akira1
1

Graduate School of Natural Science and Technology, Kanazawa University, 2 Research Institute for Sustainable Humanosphere,
Kyoto University
Further reductions in mass, volume, and power of analog circuits are important in developing scientific instruments of plasma
wave observations. Typical plasma wave receiver is roughly divided into two types: one is a waveform receiver and the otheris a spectrum one. The waveform receiver provides a waveform with a high time resolution and phase information of a plasma
wave. On the other hand, the spectrum receiver provides a frequency spectrum with a high frequency resolution and a highsignal-to-noise ratio in comparison with waveform receivers.
We have been developing a plasma waveform receiver using Application Specific Integrated Circuit (ASIC) technology. Previous ASIC waveform receiver consists of a differential Gm-C Low-Path Filter (LPF), a main amplifier for the gain adjustment,a switched capacitor LPF for anti-aliasing with the cutoff frequency of 100 kHz, and a Gm-C LPF for reducing the clock pulse
noise of the switched capacitor LPF. The previous ASIC receiver shows a sufficient low noise performance (210 nV/sqrt(Hz) at
10 kHz) and low power consumption (60 mW). However, the dynamic range of output voltage is not sufficient due to using operational transconductance amplifiers (OTAs) of Gm-C LPFs. In order to improve the dynamic range of the ASIC receiver, we haveredesigned the ASIC receiver to exclude OTAs. In this study, we used active LPFs consisting of operational amplifiers (OPAs)
instead of Gm-C LPFs using OTAs. As a result, the dynamic range increased by 80%. Moreover, the layout area decreased by
18%, and the number of transistors decreased by 60% in comparison with the previous ASIC receiver.
In this presentation, we will present the design principles of our ASIC receiver for plasma wave observations and discuss its
electrical performances in detail.

Keywords: Analog ASICs, Plasma waveform receiver

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PCG31-P05

Room:Convention Hall

Time:May 27 18:15-19:30

A model calculation of MIA sensor characteristics on board MMOMIYAZAKI, Shoichi1∗ ; MIYAKE, Wataru2 ; SAITO, Yoshifumi3 ; YOKOTA, Shoichiro3
1

Graduate School of Engineering, Tokai University, 2 School of Engineering, Tokai University, 3 ISAS

MIA is an electrostatic analyzer, on board MMO. The objectives are studies of plasma environment around Mercury. According
to the result of ground test, it has performance almost as designed. This analyzer design is axial symmetric. However, thecharacteristics are depending on angle of ions’ incidence. Assuming that the dependence is caused by slight unexpected shiftof cylindrical 3 parts; inner and outer plates, top-hat plate. In this paper, first of all, we calculate two-dimensional and threedimensional sensor models with axial symmetry, and compare the results with the data of ground test. Then we simulate threedimensional model with asymmetry. The study will lead to designing electrostatic analyzers with high accuracy.
Keywords: MIA, MMO

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PCG31-P06

Room:Convention Hall

Time:May 27 18:15-19:30

Laboratory experiment simulating Martian surface observation with submillimeter-wave
polarimetric radiometry
ARIMURA, Taketo1∗ ; OCHIAI, Satoshi2 ; KASAI, Yasuko2 ; KIKUCHI, Kenichi2 ; KITA, Kazuyuki3
1

Graduate School of Science and Engineering, Ibaraki University, 2 National Institute of Information and Communications Technology, 3 Faculty of Science, Ibaraki University
Energy and materials exchange between the ground and atmosphere on Mars is deeply related to Martian water cycle. It is
worthwhile to observe the spatial and temporal variability of physical temperatures and material compositions in the Martiansubsurface from orbiter. Millimeter/submillimeter radiometer is expected to achieve continuously monitoring the Martian subsurface. However, such measurement has never been conducted in planetary explorations. We assess the effectiveness of thisobservation method by laboratory experiment.
By observing millimeter/submillimeter emission from the Martian subsurface in several incident angles and two polarizations, we can derive physical temperatures and permittivity of the subsurface. In order to estimate those properties from observed emissions, we need to know relationship between emissivity or/and reflectivity and the properties of surface in millimeter/submillimeter wave region. To discuss feasibility of this observation, it is necessary to experimentally demonstrate such
estimation from the millimeter/submillimeter observation. It is also important to study the effective skin depth of the material
surface in the observation.
We developed an experiment system to examine millimeter/submillimeter wave scattering and emission characteristics of thesimulated Martian surface in a chamber. The chamber is designed to measure both emission from simulated surface using a
receiver and reflection of the surface using a transmitter and a receiver. We can measure arbitrary-polarized emissions with
arbitrary incident angles by moving mirrors in the experiment system. The experiment system is designed to set up the incident
angles to an accuracy of 1 degree and measure the brightness temperatures to an accuracy of 2K.
Reflectivity measurements were made first, because emission characteristic is basically predictable from the precise reflection
measurements. In experiment, we measured the reflectivity of 2 specimens at 230 GHz frequency range, 13 incident angles (from20 to 80 per degrees in units of 5 degrees) and 2 polarizations (V and H polarized waves). We examined if we can distinguish two
different samples from the reflectivity. Samples we measured are glass and PET plates. An electric property of glass is similar to
the main component of Martian rocks and a PET has a permittivity similar to water ice in 230 GHz frequency range. The resultof this experiment shows that it is distinguishable the glass plate from the PET plate with reflectivity at 20-70 degree angles inV polarized wave. Then, we measured reflectivity of samples of two layers consisting of the PET and the glass plates at thesame conditions (frequency, incident angle and polarization) as the previous experiment. We determined the upper limit of the
thickness of the glass plate that we can detect the signal of the PET plate which is placed under the glass plate from the reflectivity
measurement at incident angles 65 and 70 degrees in V polarization. The glass thickness of the result was 3.0 mm. The effective
skin depth of the glass plate was found to be about twice of the measurement wavelength. From these experiment results, it isestimated that water ice or temperature subsurface is detectable in the depth up to twice wavelength of millimeter/submillimeterby observing radiation from the Martian subsurface. We plan to examine whether able to distinguish between a glass and a
PET by emission measurement. Furthermore, it is necessary to confirm the relationship between an effective skin depth and apermittivity of surface in future research.

Keywords: Mars, surface observation, submillimeter-wave

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