HR: 0800h
AN: SM21A-0333    [Abstracts]
TI: Numerical Calculations of Relativistic Electron Drift Loss Effect
AU: * Kim, K
EM: kckim@chungbuk.ac.kr
AF: Chungbuk National University, Dept. of Astronomy and Space Science, 410 SungBong-Ro Heungduk-gu, Cheong-ju, 361-763, Korea, Republic of
AU: Lee, D
EM: dylee@chungbuk.ac.kr
AF: Chungbuk National University, Dept. of Astronomy and Space Science, 410 SungBong-Ro Heungduk-gu, Cheong-ju, 361-763, Korea, Republic of
AU: Kim, H
EM: heekim@khu.ac.kr
AF: Kyunghee University, Dept. of Astronomy and Space Science, 1,Seocheon-dong, Giheung- gu, Yongin-si, 446-701, Korea, Republic of
AU: Lyons, L
EM: larry@atmos.ucla.edu
AF: UCLA, Dept. of Atmospheric and Oceanic Sciences, 405 Hilgard Ave., Los Angeles, CA 90095-1565, United States
AU: Lee, E
EM: eslee@ssl.berkeley.edu
AF: Space Science Laboratory, UC Berkeley, 7 Gauss Way, Berkeley, CA 94720, United States
AU: Ozturk, M
EM: mkozturk@isikun.edu.tr
AF: Isik University, Dept. of Information Technologies, Kumbaba Mevkii, ĻĢile, İstanbul, 34980, Turkey
AU: Choi, C
EM: crchoi@chungbuk.ac.kr
AF: Chungbuk National University, Dept. of Astronomy and Space Science, 410 SungBong-Ro Heungduk-gu, Cheong-ju, 361-763, Korea, Republic of
AU: Moon, Y
EM: yjmoon@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, Hwaam-dong, Yuseong-gu, Daejeon, 305- 348, Korea, Republic of
AB: It has been suggested that drift loss to the magnetopause can be one of the major loss mechanisms contributing to the relativistic electron flux dropout. In this study, we examine details of relativistic electrons' drift physics to determine the extent to which the drift loss through the magnetopause is important to the total loss of the outer radiation belt. We have numerically computed drift paths of relativistic electrons' guiding center for various pitch angles, various positions and different solar wind conditions using Tsyganenko T02 model. We specifically demonstrate how the drift loss effect depends on these various parameters. It is shown that the drift loss effect is more likely expected for a higher pitch angle and near midnight and then spreads to lower pitch angles and dusk and dawn MLT regions as the dynamic pressure increases or IMF B_Z becomes more southward. Most importantly, we present various estimates of relative changes of omni-directional flux of 1MeV electrons between two different solar wind conditions based on a simple form of the directional flux function. For a change of the dynamic pressure from 4 nPa to 10 nPa with a fixed IMF B_Z=0 nT, our estimate indicates that the omni- directional flux for the 10 nPa pressure at the equator at midnight near geosynchronous altitude decreases by ~56 to 97%, depending on a specific pitch angle dependence of the directional flux function, compared to that for the 4 nPa pressure. The effect is somewhat lower at pre- and post-midnight MLTs, and rapidly declines at inner regions than geosynchronous orbit. It however becomes more substantial at measurement positions away from the equator. A qualitatively similar, but quantitatively different, result has been obtained for two different conditions of IMF B_Z.
DE: 2720 Energetic particles: trapped
DE: 2753 Numerical modeling
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting