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Simulation of a Rapid Dropout Event for Highly Relativistic Electrons with the RBE ModelA flux dropout is a sudden and sizable decrease in the energetic electron population of the outer radiation belt on the time scale of a few hours. We simulated a flux dropout of highly relativistic 2.5 MeV electrons using the Radiation Belt Environment model, incorporating the pitch angle diffusion coefficients caused by electromagnetic ion cyclotron (EMIC) waves for the geomagnetic storm events of 23-26 October 2002. This simulation showed a remarkable decrease in the 2.5 MeV electron flux during main phase of the storm, compared to those without EMIC waves. This decrease was independent of magnetopause shadowing or drift loss to the magnetopause. We suggest that the flux decrease was likely to be primarily due to pitch angle scattering to the loss cone by EMIC waves. Furthermore, the 2.5 MeV electron flux calculated with EMIC waves correspond very well with that observed from Solar Anomalous and Magnetospheric Particle EXplorer spacecraft. EMIC wave scattering is therefore likely one of the key mechanisms to understand flux dropouts. We modeled EMIC wave intensities by the Kp index. However, the calculated dropout is a several hours earlier than the observed one. We propose that Kp is not the best parameter to predict EMIC waves.
Document ID
20170003509
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kang, S-B. (Universities Space Research Association Greenbelt, MD, United States)
Fok, M.-C. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Glocer, A. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Min, K.-W. (Korea Advanced Inst. of Science and Technology Daejeon, Korea, Republic of)
Choi, C.-R. (Korea Advanced Inst. of Science and Technology Daejeon, Korea, Republic of)
Choi, E. (Maryland Univ. Baltimore County Baltimore, MD, United States)
Hwang, J. (Korea Astronomy and Space Science Inst. Korea, Republic of)
Date Acquired
April 17, 2017
Publication Date
May 7, 2016
Publication Information
Publication: Journal of Geophysical Research: Space Physics
Volume: 121
Issue: 5
ISSN: 2169-9380
Subject Category
General
Report/Patent Number
GSFC-E-DAA-TN41219
Funding Number(s)
WBS: WBS 936723.02.01.09.47
CONTRACT_GRANT: NNG11PL02A
CONTRACT_GRANT: NNH15CO48B
Distribution Limits
Public
Copyright
Other