Aiming at future secure/safe space use by understanding the particle acceleration and loss in the inner magnetosphere
Out of various types of geo space, the center of the inner magnetosphere is outside the earth, and the distance between the earth center and inner magnetosphere center is especially approximately four times of the earth radius. The inner magnetosphere contains plasma particles (electrons and ions) in wide energy ranges from the radiation belt configured with high-energy plasmas to the plasmasphere configured with low-energy plasmas. This sphere is an interesting area in which particles are accelerated and lost as interacting with electromagnetic waves.
In the inner magnetosphere, because of the gradient and curvature of the geomagnetic field, plasma particles are accelerated and lost as rotating round the earth in the longitudinal direction in periods of several tens of minutes to several hours.
So, it is indispensable for quantitative understanding of the dynamical variation of the particles and electromagnetic field to grasp the dynamical variation field eccentrically located at a particular longitude on a global scale. The objectives of this study are to grasp the process of dynamical variation of the particles and waves in this inner magnetosphere and clarify the mechanism of the dynamical variation quantitatively.
The global distribution of the particles and waves rotating round the earth has not been understood by observation so far.
So, based on international collaboration, this project establishes eight ground-based stations separately positioned in the longitude direction along a latitude line, and observes how the particles rotating round the earth in the space around the earth fall into the earth atmosphere and interact with waves, making it possible to monitor the global conditions of the particles and waves 24 hours a day.
The mechanism of the dynamical variation in the inner magnetosphere can be evaluated quantitatively using this network-based observation on the earth, direct observation of the magnetosphere by Japan’s new ERG satellite launched in fiscal 2016, and modeling in combination.
It is known that the high-energy plasmas in the inner magnetosphere including the radiation belt particles cause functional problems such as the internal charge and memory inversion of artificial satellites, degradation of solar battery panels, or communication failures. In addition, the radiation belt particles accelerated in the magnetosphere influence radiation dose for astronauts.
The result of this study will contribute to the improvement of the prediction accuracy in the space radiation environment. It will also be utilized for prediction and evaluation of the failures of artificial satellite equipment, being helpful with the use of space.
PWING stands for "study of dynamical variation of Particles and Waves in the INner magnetosphere using Ground-based network observations."
|OTSUKA, Yuichi Associate professor, Nagoya University||Creation of electron density map of the ionosphere using the GNSS receiver network, also being in charge of data collection from the ground-based stations via the network.|
|OYAMA, Shin-ichiro Lecturer, Nagoya University||In charge of ground-based observations in Alaska and Finland.|
|NISHITANI, Nozomu Associate professor of Nagoya University||Primarily in charge of ground-based stations in Russia, creating a global map of plasma convection using the data collected by a SuperDARN HF radar network.|
|NOSE, Masahito Associate professor of Nagoya University||In charge of observation at ground-based stations in Kapuskasing and Nain, Canada.|
|MIYOSHI, Yoshizumi Professor of Nagoya University||Project scientist of the ERG satellite, being in charge of observation using an EMCCD camera, development of global models, and building of the observation database.|
|OZAKI, Mitsunori Associate professor of Kanazawa University||Development of loop antennas to observe VLF/ELF waves at frequencies of 0.1 to 10 kHz.|
|KATAOKA, Ryuho Associate professor of NIPR (the National Institute of Polar Research)||High-speed imaging of aurora using EMCCD cameras.|
|SEKI, Kanako Professor of Tokyo University||Evaluation of particle acceleration and loss quantitatively by developing a model of interaction between global waves and particles and utilizing the model for observation.|
|TANAKA, Yoshimasa Specially appointed associate professor of NIPR||Observation of high-energy electrons precipitation from space by developing a broad beam riometer.|
|SHINOHARA, Iku Associate professor of ISAS/JAXA.||Project manager of the ERG satellite, promoting collaboration with satellite observation.|
|NAGATSUMA, Tsutomu Research manager of NICT||Measurement of ULF waves at frequencies from 0.1 to 10 Hz using induction magnetometers.|
|SAKANOI, Takeshi Associate professor of Tohoku University||Optical observation in Canada.|
|TSUCHIYA, Fuminori Associate professor of Tohoku University||Observation of standard transmitter radio waves in Russia, Canada, and Norway to study the variation of the ionospheric D-layer due to the precipitation of high-energy electrons.|
|OBANA, Yuki Research Fellow of Kyushu University||Fieldworks in Canada and diagnostics of the plasmasphere using the data from the magnetometers.|
|SUZUKI, Shin Professor of Aichi University||Observation in Canada, and study of the waves of the upper atmosphere using the data obtained by all-sky airglow/aurora cameras.|
|SHINBORI, Atsuki Designated assistant professor, Nagoya University.||Study of global dynamics of ionosphere and plasmasphere during geomagnetic disturbances using GPS-TEC data.|
|SANDEEP Kumar Researcher, Nagoya University.||Investigation of plasma wave and particle changes in the inner magnetosphere using ground-based, satellite and model data.|
|TAKAHASHI, Naoko Researcher, National Institute of Information and Communications Technology.||Modeling of Geospace environmental change.|
|KATO, Yasuo Technical staff of Nagoya University||Support for development of riometers and VLF antennas.|
|HAMAGUCHI, Yoshiyuki Technical staff of Nagoya University||Support for development of induction magnetometers and VLF antennas.|
|YAMAMOTO, Yuka Technical staff of Nagoya University||Support for development of all-sky cameras, VLF antennas, data aquisition softwares, and internet connection.|
|ADACHI, Takumi Technical staff of Nagoya University||Support for the overall system developments and GPS clocks.|
Spatial distribution can be understood globally by observing waves and particles simultaneously at new 8 ground-based stations.
●Existing ground-based stations
★New ground-based stations
A list of the academic papers of this study can be viewed from here. (PDF file）