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작성일 : 17-05-26 13:25
05월 30일(화요일) 우주과학과 세미나 안내(강석빈박사님)
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안녕하세요우주과학과 여러분.
이번 세미나는 5 30일 오후 4 30천문대 영상실에서 있습니다.
 Geospace Physics Lab., NASA/GSFC의 강석빈 박사님께서 "지구 자기권에서 자기력선 곡률과 입자 수송에 의한 고에너지 전자 손실"에 관한 강연을 해 주실 예정입니다. 강연은 한국어로 진행되며초록은 아래에 나타나있습니다.
세미나 참석을 원하시는 분은 세미나 시작 10분 전까지 입실해 주시기 바랍니다.
많은 참석 부탁드립니다감사합니다.
Dear Colleagues,
There will be an Astronomy and Space Science seminar on 05/30, 4:30 PM, in the Auditorium, Kyung Hee University Astronomical Observatory.
Dr. Suk-Bin Kang of Geospace Physics Lab., NASA/GSFC will give a presentation about "Relativistic electron flux dropout due to radial transport and field-line-curvature in the Earth inner magnetosphere".
The language of the seminar will be Korean and abstract is shown below.
You are asked to join the seminar five to ten minutes before it starts. Your attendance will greatly be appreciated.
Thank you.
A relativistic flux dropout is sudden and significant decrease in the relativistic electron (> 1 MeV) population of the outer radiation belt occurring over timescales of a few hours. A significant dropout of relativistic electrons was observed by Van Allen Probes during the storm main phase on June 1, 2013. During the same period, MeV electron precipitation with isotropic pitch-angle distribution was also observed from POES but no EMIC waves were detected from either space- or ground-based magnetometers. Based on Tsyganenko empirical magnetic field model, magnetic field lines are highly non-dipolar and stretched at the night side in the inner magnetosphere. This condition can break the first adiabatic invariant (conservation of magnetic moment) and generate pitch-angle scattering of relativistic electron to the loss cone. Another possible loss mechanism is drift loss from close to open drift shells. During a storm, highly disturbed magnetic field configuration can adiabatically and/or diffusively enhance drift loss of electrons with local magnetic maximum/minimum (referred to as magnetic islands). To understand the relative roles of different physical mechanisms on this dropout event, we simulate flux and phase space density of relativistic electrons with event specific plasma wave intensities using the Comprehensive Inner Magnetosphere and Ionosphere (CIMI) model. We also employ pitch-angle scattering due to field line curvature in the CIMI model. We re-configure magnetic field every minute and update electric field every 20 seconds to capture convective and diffusive radial transport. CIMI-simulation with pitch-angle scattering due to field line curvature shows more depletion of relativistic electron fluxes and better agreement to observation. Sudden decrease in the L* of last close drift shell We conclude that pitch-angle scattering due to field line curvature and drift loss are the dominant processes for the relativistic electron flux dropout.