| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1993: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1992: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
This is one of a series of the basic research projects which aim at better understanding and estimating plasma convection in the magnetosphere on the basis of information primarily of ground-based magnetometer data. Starting with improving the so-called magnetogram-inversion technique combined effectively with observations of the high-latitude ionosphere by means of coherent and incoherent scatter radars and polar-orbiting satellites, it has been attempted (1) to separate large-scale convection electric fields from substorm-associated, localized electric fields, (2) to obtain the local time dependence of the auroral electrojets, and (3) to prove (or disprove) that the auroral electrojets during substorm expansion consists of two elements representing two solar wind-magnetosphere coupling processes ; i.e., the directly driven process and the loading-unloading process.
The following are the main findings :
1. Examining data of the ionospheric conductivity and the electric field from detailed observation by EISCAT, it is found that there is a significant degree of the height dependence in ionospheric currents, and that near 120 km, the pedersen currents have north-south components as well.
2. The deformation of the global potential destribution during substorms is chracterized by summation of two potential systems, which are the so-called twin vortex pattern centered at dawn and dusk sectors and the substorm-expansion potential distribution centered in the midnight sector.
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