資料8-H

Japanese URSI Commission H (Waves in Plasmas)
Activity Report
March- June, 2013[1] Status of projects related with plasma wave observation
1. NICT Science Cloud
Major methodologies of Solar-Terrestrial Physics (STP) including space plasma
data analysis so far are (1) theoretical, (2) experimental and observational, and (3)computer simulation approaches. Recently "informatics" is expected as a new(fourth) approach to the STP studies is a methodology to analyze large-scale data
(observation data and computer simulation data) to obtain new findings using avariety of data processing techniques. What is the infrastructure required for the
fourthmethodologyis“cloudcomputingsystem”.

The

cloud

computingenvironments should play significant roles in the STP science. At NICT (National
Institute of Information and Communications Technology) we are now developing a
new research environment for the 4th methodology named “NICT Science Cloud”.
One of the advantages of the NICT Science Cloud to the legacy (traditional) data
analysis environments is its integrated resources. The NICT Science Cloud
provides the researchers with rich computational resources for research studies,such as super-computer, large-scale storage (disk) area, data processing parallelcluster workstations with GPGPUs, licensed applications, DB (database) andmeta-DB, and communication devices. The background (backbone) network for the
NICT Science Cloud is the JGN-X (Japan Gigabit Network), which connects many
computer resources with as high-speed network as 1Gbps to 40Gbps.
For the large-scale data analysis for STP data files, we have implemented a
distributed data analysis servers in the NICT Science Cloud. There are 23 servers
with 276 CPUs distributed at five data centers. These 23 servers are clients ofGfarm/Pwrake, which is a middle-ware for both distributed data storage andparallel data processing. The Gfarm/Pwrake shows a great performance forlarge-scale data analysis on such a wide-area distributed cloud environment.
2. Akebono (EXOS-D)
The Akebono spacecraft has attained the 24 years of successful operation without
any major troubles. The regular data acquisition of MGF, PWS, VLF, TED, andRDM is continued at stations in Japan and Sweden. The operation of the Akebono
operation will be extended until March, 2015 (FY2014) in order to realize
collaborative measurements with the Van Allen Probes, and further extension to the1end of FY2016 is expected as an optional mission. Detailed information on the
Akebonodatasetisavailableonthewebsiteof

DARTS/AKEBONO(http://www.darts.isas.jaxa.jp/stp/akebono/).
[General information: http://www.jaxa.jp/projects/sat/akebono/index_e.html]
3. CRUX magnetometers
In order to study spatial structure of quarter-wave mode of field line resonances,
Osaka Electro-Communication University operates magnetometer sites in New
Zealand. Currently they are collecting data from Te Wharau (L-value 2.2 Re) andMiddlemarch

(2.8

Re)

stations.

For

more

information,see

http://www1.osakac.ac.jp/crux/.
4. Special Issue of Earth, Planets and Space entitled “Physical Processes in
Non-Uniform Finite Magnetospheric Systems -50 Years of Tamao's Resonant Mode
Coupling Theory” (Earth Planets Space, Vol. 65, No. 5, 2013)This special issue of Earth, Planets and Space is published to commemorate theWorkshop on Physical Processes in Non-Uniform Finite Magnetospheric Systems, 50 Years of Tamao's Resonant Mode Coupling Theory -, held in Fukuoka, Japan, in
12-15, September, 2011. This international workshop was held on the occasion of
the 50 years’ anniversary of the publication of Professor Tamao’s pioneering paperon the resonant mode coupling of magnetohydrodynamic waves in themagnetosphere.

The workshop was proposed and organized by an internationalteam of scientists who respected Prof. Tamao’s great contribution. More than 60
participants from many countries discussed recent progress and future perspectives
about the resonant mode coupling and other topics in which a non-uniform andfinite system is essential. For example, the resonant mode coupling theory isapplied to sounding of the Earth’s magnetosphere, and the MHD waves in Herman
and other planets’ magnetospheres are studied in terms of this theory. In addition,
the magnetosphere-ionosphere coupling study is now developed to research of themagnetosphere-ionosphere compound system in which many elementary processes
are self-consistently coupled. The new method was also presented to separate
upward and downward propagating Alfven waves from the wave signals observed
above the ionosphere. 8 papers from the participants are published.

[2] Recent Meetings
1.

Symposium on Electromagnetospheric Physics (Organizers: H. Kawano and2

K. Shiokawa), Fukuoka, Japan, March 4-5, 2013.
2.

JpGU (Japan Geoscience Uniton) Meeting 2013, Makuhari, Japan, May 19-24,
2013.

3.

AOGS(Asia Oceania Geosciences Society) 2013, Brisbane, Australia, June 24-28,
2013.

[3] Future 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.
4. COSPAR Symposium on “Planetary Systems of our Sun and other Stars, and the
Future of Space Astronomy”, Bangkok, Thailand, November 11-15, 2013.
5. International CAWSES (Climate and Weather of the Sun-Earth System)-II
Symposium, Nagoya, Japan, November 18-22, 2013.

[4] Recently Published Papers (March 2013 – June 2013)
1.

Kubota, Y., Yamamoto, K., Fukazawa, K., and Murata, K. T., Visualization of theFlux Rope Generation Process Using Large Quantities of MHD Simulation Data,
Data Science Journal, Vol.12, pp.WDS134-WDS138, Apr., 2013.
We present a new concept of analysis using visualization of large quantities ofsimulation data. The time development of 3D objects with high temporal
resolution provides the opportunity for scientific discovery. We visualize large
quantities of simulation data using the visualization application 'Virtual Aurora'
based on AVS (Advanced Visual Systems) and the parallel distributed processingat "Space Weather Cloud" in NICT based on Gfarm technology. We introduce two
results of high temporal resolution visualization: the magnetic flux rope
generation process and dayside reconnection using a system of magnetic field line
tracing.

2.

Kunitake, M., Yamamoto, K., Watari, S., Ukawa, K., Kato, H., Kimura, E.,
Murayama, Y. and Murata, K. T., Solar-Terrestrial Data Analysis and Reference
System (STARS) – Its High Potentiality for Collaborative Research, Data Science
Journal, Vol.12, pp.WDS225-WDS228, Apr., 2013.
Cross-sectional studies have become important for an improved understanding of3

various Solar-Terrestrial Physics (STP) fields, given the great variety anddifferent types of observations from the Sun to the Earth. In order to better
combine, compare, and analyze different types of data together, a system named
STARS (Solar-Terrestrial data Analysis and Reference System) has beendeveloped. Cross-sectional study requires cooperative work. STARS has twofunctions for cooperative work, the "Stars Project List (SPL)" and the "Event
Listing". The SPL is used for exchanges of plotting information by cooperating
persons. The event list database provides all users of STARS hints for recognizing
typical occurrences of STP phenomena.
3.

Murata, K. T., Watari, S., Nagatsuma, T., Kunitake, M., Watanabe, H., Yamamoto,K., Kubota, Y., Kato, H., Tsugawa, T., Ukawa, K., Muranaga, K., Kimura, E., Tatebe,
O., Fukazawa, K. and Murayama, Y., A Science Cloud for Data Intensive Sciences,
Data Science Journal, Vol.12, pp.WDS139-WDS146, Apr., 2013.
It is often discussed that the fourth methodology for science research is"informatics". The first methodology is a theoretic approach, the second one isobservation and/or experiment, and the third one is computer simulation.
Informatics is a new methodology for data intensive science, which is a newconcept based on the fact that most scientific data are digitalized and the amountof data is huge. The facilities to support informatics are cloud systems. Herein we
propose a cloud system especially designed for science. The basic concepts, design,
resources, implementation, and applications of the NICT science cloud are
discussed.

4.

Watanabe, H., Yamamoto, K., Tsugawa, T., Nagatsuma, T., Watari, S., Murayama, Y.
and Murata, K. T., An Integrated Management System of Multipoint Space
Weather Observation, Data Science Journal, Vol.12, pp.WDS175-WDS178, Apr.,2013.
An outline of a planned system for the global space-weather monitoring network
of NICT (National Institute of Information and Communications Technology) is
given. This system can manage data collection much more easily than our current
system by installations of autonomous recovery, periodical state monitoring, anddynamic warning procedures. According to a provisional experiment using a
network simulator, the new system will work under limited network conditions,e.g., a 160 msec delay, a 10 % packet loss rate, and a 500 Kbps bandwidth.

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5.

Watari, S., Kato, H., Murata, K. T., Yamamoto, K., Watanabe, H., Kubota, Y. andKunitake, M., Research Environment and Information Service of Space Weather
Cloud, Data Science Journal, Vol.12, pp.WDS209-WDS212, Apr., 2013.
To optimize space weather research and information services, it is important toestablish a comprehensive system that enables us to analyze observation andsimulation data in an integrated manner. For this, we recently constructed a newcomputing environment called the "Space Weather Cloud Computing System" of
the National Institute of Information and Communications Technology (NICT).
Currently, the Space Weather Cloud contains a high performance computer, a
distributed mass storage system using the Grid Data Farm (Gfarm) technology,
servers for analysis and visualization of data, a job service based on the RCM(R&D Chain Management) system, servers for Solar-Terrestrial data Analysis,
and the Reference System (STARS).

6.

Murata, K. T., Watanabe, H., Yamamoto, K., Kubota, Y., Tatebe, O., Tanaka, M.,
Fukazawa, K., Kimura, E., Ukawa, K., Muranaga, K., Suzuki, Y., Isoda, F., A
Parallel Processing Technique on the NICT Science Cloud via Gfarm/Pwrake (inJapanese), IPSJ HPC SIG Technical Reports, Vol.2013-HPC-139, No.9, pp.1-6,
2013.
For data intensive science on cloud systems, we need development of techniques
for DIC (Data-Intensive Computing) as well as HTC (High-Through-put
Computing), MTC (Many-Task Computing), and HPC (High-Performance
Computing). The DIC is a new concept of large-scale data processing paying
attentions to data distribution, data-parallel execution, and harnessing data
locality by scheduling of computations close to the data. As the data file size isgetting larger, I/O time to read and/or write data is not negligible compared withdata processing time. We herein develop a DIC technique on a science cloud using
Gfarm/Pwrak. The Gfarm/Pwrake has been developed as an integrated system ofboth distributed file system and parallel data processing system. With identifying
file system nodes (FSN) and processing client node (CN) and giving higher
priority to process files on the local disk than on remote disks, we succeeded inprogress of total performance in processing large-scale data files.

7.

Watanabe, H., Kurosawa, T., Ichioka, S., Kimura, E., Murata, K. T., Tatebe, O.,
Parallel File Transfer using UDT (in Japanese), IPSJ HPC SIG Technical Reports,
Vol.2013-HPC-139, No.8, pp.1-8, 2013.

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High-speed data migration remains one of problem in the high-performance
distributed computing. There are researches to improve end-to-end data I/O
performance in a LFN(Long Fat Network), but most of them have been developed
for a one-to-one data transfer. In fact, they are not the easy technology to use in
the case of a one-to-many data transfer because users such as science researchers
are forced to develop a function to control parallel data transfer. We propose theparallel data transfer system using UDT, and confirmed about 7Gbps data I/O
performance (download) of the proposed system in the both local evaluation
experiment and global evaluation experiment.
8.

Isoda, F., Murata, K. T., Watanabe, H., Fukazawa, K., Yamamoto, K., Tatebe, O.,
Tanaka, M., Kimura, E., High Performance of Big Data Processing via NICT
Science Cloud (in Japanese), IEICE-SC2013-4, Vol. IEICE-113, No.86, pp.19-24,
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 100 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.

9.

Murata, K. T., Watanabe H.,, Ukawa, K., Muranaga, K., Suzuki, Y., Isoda, F.,
Yamamoto, K., Tatebe, O., Tanaka, M., Kimura, E., Satoh, S., The NICT Science
Cloud -- A Proposal of Cloud System for Scientific Researches – (in Japanese),
IEICE-SC2013-2, IEICE-113, No.86, pp.5-11, 2013.
This paper is to propose a cloud system for science, which has been developed at
NICT (National Institute of Information and Communications Technology),
Japan. The NICT science cloud is an open cloud system for scientists who are6going to carry out their informatics for their own science. The NICT science cloudis not for simple uses. Many functions are expected to the science cloud; such asdata standardization, data collection and crawling, large and distributed data
storage system, security and reliability, database and meta-database, data
stewardship, long-term data preservation, data rescue and preservation, data
mining, parallel processing, data publication and provision, semantic web, 3D
and 4D visualization, out-reach and in-reach, and capacity buildings.
10. Watanabe, H., Iwama, T., Murata, K. T., Ukawa, K., Muranaga, K., Suzuki, Y.,
Kimura, E., Tatebe, O., Takasugi, H., Kamezawa, Y., NICT Science Cloud -- An
Extension of Security Functions in a Wide-Area Distribution File System -- (inJapanese), IEICE-SC2013-3, IEICE-113, No.86, pp.13-18, 2013.
The NICT Science Cloud is a cloud system specialized for scientific research
activities. One of the important functions provided by the NICT Science Cloud isa wide-area distributed file system, as wide as over Japan. This file system isimplemented by a middle-ware, named Gfarm (Grid datafarm). The wide-area
storage system is operated on the cloud system, maintaining several tens of
millions of scientific data files. For more reliable and safety operation of the filesystem, we need development of security system designed for such wide-area filesystems. In the present study, we demonstrate our science cloud system focusing
on the file system. Addressed are the issues for the secure and reliable wide-area
file system in the present discussions.
11. Fujita, S., and T. Tanaka, Possible generation mechanisms of the Pi2 pulsations
estimated from a global MHD simulation, Earth Planets Space, 65, pp. 453-461,
2013.
The plasmaspheric virtual resonance (PVR) and the transient Alfven wave bouncing between
the ionospheres in both hemispheres (the transient response, TR) are regarded as the possible
generation mechanisms of the Pi2 pulsations. However, the global MHD simulation of a
substorm [Tanaka et al., 2010] did not reproduce such wave modes because of insufficient
ionospheric reflection of the Alfven wave, numerical transfer of the Alfven wave across thefield lines, and no plasmasphere.

Furthermore, it is noted that the substorm current wedge(SCW) which is a driver of the TR is not reproduced in the global MHD simulation.

In thisstudy, we search the sources of the Pi2 pulsations in the global MHD simulation, namely, thecompressional wave in the inner magnetosphere for the PVR and the Alfven wave injected tothe ionosphere for the TR. In conclusion, there appears a compressional signal in the inner7

magnetosphere when the high-speed Earthward flow at the substorm onset surges in the inneredge of the plasma sheet.
12. Kokubun, S., ULF waves in the outer magnetosphere: Geotail observation 1
transverse waves, Earth Planets Space, 65, pp. 411-433, 2013.
A survey of ULF waves in the Pc 5 frequency range during the six year period (1995-2000)
has been made for the field line resonance waves in the outer magnetosphere, using plasma
flow and magnetic field measurements with the Geotail spacecraft. On the morning side aseries of wave trains often appears during several hours. In contrast such a series of wave
trains with a long duration is rarely observed in the afternoon to evening sector. Most ofwaves in the afternoon sector are isolated, of which duration is approximately one hour. The
existence of a set of preferential frequencies and the pronounced dawn-dusk asymmetry ofwave occurrence and wave features, which were found in ground-based and ionosphericmeasurements of geomagnetic ULF pulsations, were statistically confirmed. It is also notedthat the background plasma flow is sunward in the evening sector without exception.
Transverse waves are generally observed in the condition of plasma β below 1.5. High βcases are mostly associated with events on the dusk side. As for the relation to solar windconditions, Pc 5 waves tend to occur under the condition of more radial than the average IMF
spiral angle, or of low cone angle.
13. Pilipenko, V. A., H. Kawano, and I. R. Mann, Hodograph method to estimate thelatitudinal profile of the field-line resonance frequency using the data from two
ground magnetometers, Earth Planets Space, 65, 435–446, 2013.
The hodograph method enables estimating the latitudinal profile of the field-line resonance(FLR) frequency (fR) using the data from two ground magnetometers. This paper provides
the full details of this method for the first time, and uses a latitudinal chain of groundmagnetometers to examine its validity and usefulness. The hodograph method merges the
widely-used amplitude-ratio and cross-phase methods in a sense that the hodograph method
uses both the amplitude ratio and the phase difference in a unified manner; further than that,the hodograph method provides fR at any latitude near those of the two groundmagnetometers. It is accomplished by (1) making a complex number by using the amplitude
ratio (phase difference) as its real (imaginary) part; (2) drawing thus obtained complex
numbers (one number for one frequency) in the complex plane to make a hodograph; and (3)fitting to thus obtained hodograph a model satisfying the FLR condition, which is a circle
with the assumption that the resonance width is independent of the latitude.

814. Grison, B., O. Santolik, N. Cornilleau-Wehrlin, A. Masson, M. J. Engebretson, J. S.
Pickett, Y. Omura, P. Robert, R. Nomura, EMIC triggered chorus emissions in
Cluster data, J. Geophys. Res., 118, doi:10.1002/jgra.50178, 2013.
Electromagnetic ion cyclotron (EMIC) triggered chorus emissions have recently been asubject of several experimental, theoretical and simulation case studies, noting theirsimilarities with whistler-mode chorus. We perform a survey of 8 years of Cluster data inorder to increase the database of EMIC triggered emissions. The results of this is that EMIC
triggered emissions have been unambiguously observed for only three different days. These
three events are studied in detail. All cases have been observed at the plasmapause between
22 and 24 magnetic local time (MLT) and between –15 degrees and 15 degrees of magnetic
latitude. Triggered emissions are also observed for the first time below the local helium
gyrofrequency. The number of events is too low to produce statistical results, nevertheless wepoint out a variety of common properties of those waves.
15. Y. Katoh, M. Kitahara, H. Kojima, Y. Omura, S. Kasahara, M. Hirahara, Y. Miyoshi,
K. Seki, K. Asamura, T. Takashima, and T. Ono, Significance of Wave-Particle
Interaction Analyzer for direct measurements of nonlinear wave-particle
interactions, Ann. Geophys., 31, 503?512, 2013.
In the upcoming JAXA/ERG satellite mission, Wave Particle Interaction Analyzer (WPIA)
will be installed as an onboard software function. We study the statistical significance of the
WPIA for measurement of the energy transfer process between energetic electrons andwhistler-mode chorus emissions in the Earth’s inner magnetosphere. The WPIA measures a
relative phase angle between the wave vector E and velocity vector v of each electron andcomputes their inner product W, where W is the time variation of the kinetic energy ofenergetic electrons interacting with plasma waves. We evaluate the feasibility by applying
the WPIA analysis to the simulation results of whistler-mode chorus generation. We compute
W using both a wave electric field vector observed at a fixed point in the simulation system
and a velocity vector of each energetic electron passing through this point. By summing up
Wi of an individual particle i to give Wint, we obtain significant values of Wint as expectedfrom the evolution of chorus emissions in the simulation result.
16. K. Yamaguchi, T. Matsumuro, Y. Omura, and D. Nunn, Ray tracing ofwhistler-mode chorus elements: implications for generation mechanisms of risingand falling tone emissions, Ann. Geophys., 31, 665-673, 2013.
Using a well-established magnetospheric verylow-frequency (VLF) ray tracing method, in
this work we trace the propagation of individual rising- and fallingfrequency elements of9

VLF chorus from their generation point in the equatorial region of the magnetospherethrough to at least one reflection at the lower-hybrid resonance point. Unlike recent work by
Bortnik and co-workers, whose emphasis was on demonstrating that magnetospheric hiss has
its origins in chorus, we here track the motion in the equatorial plane of the whole chorus
element, paying particular regard to movement across field lines, rotation, and compression
or expansion of the wave pulse. With a generation point for rising chorus at the equator, it
was found the element wave pulse remained largely field aligned in the generatin regions.
However, for a falling tone generation point at 4000 km upstream from the equator, by thetime the pulse crosses the equator the wavefield had substantial obliquity, displacement, andcompression, which has substantial implications for the theory of falling chorus generation
17. A. Kakad, Y. Omura, B. Kakad, Experimental evidence of ion acoustic soliton chain
formation and validation of nonlinear fluid theory, Phys. Plasmas, 20, 062103,
2013.
We perform one-dimensional fluid simulation of ion acoustic (IA) solitons propagating
parallel to the magnetic field in electron-ion plasmas by assuming a large system length. To
model the initial density perturbations (IDP), we employ a KdV soliton type solution. Our
simulation demonstrates that the generation mechanism of IA solitons depends on the
wavelength of the IDP. The short wavelength IDP evolve into two oppositely propagating
identical IA solitons, whereas the long wavelength IDP develop into two indistinguishable
chains of multiple IA solitons through a wave breaking process. The wave breaking occurs
close to the time when electrostatic energy exceeds half of the kinetic energy of the electron
fluid. The wave breaking amplitude and time of its initiation are found to be dependent on
characteristics of the IDP. The strength of the IDP controls the number of IA solitons in thesolitary chains. The speed, width, and amplitude of IA solitons estimated during their stablepropagation in the simulation are in good agreement with the nonlinear fluid theory. This
fluid simulation is the first to confirm the validity of the general nonlinear fluid theory, which
is widely used in the study of solitary waves in laboratory and space plasmas.

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