Developmental Research for Establishing Measurement Techniques of Multi-Composition Space Plasma over a Wide Energy Range and Elucidating the Space Plasma Interaction in Geospace

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In order to realize the wide energy-range measurement in the in-situ geospace plasma/particle observations, we have developed the following elements/facilities:1. High-performance and multi-functional ion/electron beam line producing the parallel and large profile over the energy range of 8-200 keV2. High-energy particle instrument using the time-of-flight technique and strip-type Silicon solid-state detector arrays3. Medium-energy plasma instruments using the cusp-type electrostatic analyzer, the time-of-flight technique, and strip-type Silicon solid-state detector arrays4. Simple ion/electron beam line for the energy range of 10-120 keVThese beam line would be useful and sometimes crucial when we are developing several sets of plasma/particle instruments for the future exploration missions in parallel. On the basis of international collaboration, the same type of the beam line is also being fabricated overseas. An actual plasma instrument for the future mission is also under the deve … More lopment through a collaborative research.As the comprehensive data analysis and modeling works, numerous types of observational results obtained by on-going or previous satellite missions have been surveyed and considered for the synthetic interpretation/understanding of the geospace environment, especially during space storm and substorm. The following scientific issues are addressed:1. The comprehensive studies using satellite/ground-based observations and simulation have suggested that the medium-energy ions with 1-100 keV energies, trapped by the geomagnetic field, are essential not only for producing the ring current but for changing the electrostatic potential distribution significantly in the geospace via their field-aligned current effects.2. The high-(>100 keV) and medium(1-100 keV)-energy ions are strongly coupled each other through the geomagnetic field3. The oxygen ions with origins of the solar wind and the ionosphere are injected into the geospace particularly during space stormsThese results indicate that the cross-energy coupling and inter-region coupling are important for the geospace environment. Less