Exos-D Observations of Charged Particle Precipitation and Acceleration Processes
- Joseph R. Kan,
- Thomas A. Potemra,
- Susumu Kokubun and
- Takesi Iijima
Published Online: 19 MAR 2013
Copyright 1991 by the American Geophysical Union.
How to Cite
Mukai, T., Kaya, N. and Miyake, W. (1991) Exos-D Observations of Charged Particle Precipitation and Acceleration Processes, in Magnetospheric Substorms (eds J. R. Kan, T. A. Potemra, S. Kokubun and T. Iijima), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM064p0277
- Published Online: 19 MAR 2013
- Published Print: 1 JAN 1991
Print ISBN: 9780875900308
Online ISBN: 9781118663981
- Magnetospheric substorms—Congresses
The LEP (low energy particle) instrument on-board EXOS-D makes comprehensive measurements of energy and pitch-angle distributions of electrons and ions along with mass per charge analysis of positive ions. In this paper we discuss three topics on particle distributions in the polar region. (1) The clear energy dispersion of ions observed in the polar cusp can be interpreted in terms of the modified velocity filter effect in spite of complexities in the electric field. (2) With regard to the upflowing ion conics, altitude variations of the cone angle and the temperature demonstrate that the perpendicular ion energization often takes place over a wide altitude range. (3) The existence of the parallel electric field simultaneously below and above the spacecraft is often suggested by observations of ions and electrons. In order to explain the difference in the energy dependencies of upflowing ion beams by the species, we propose a new acceleration model, in which the region of the parallel electric field is confined in a narrow region, which moves upward and/or downward and whose potential drop is smaller at lower altitudes.