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작성일 : 14-05-08 09:49
5월 13일(화) 우주과학과 세미나 안내
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안녕하세요. 우주과학과 우주탐사학과 여러분.
 
세미나 공지 드리겠습니다.
 
 
이번 세미나는 5월 13일 오후 4시 30분 천문대 영상실에서 있습니다.
 
APL Johns Hopkins Univ., U.S. 의 Kazue Takahashi 박사님 께서 "Externally driven plasmaspheric ULF waves observed by the Van Allen Probes" 라는 제목의 강연을 해 주실 예정입니다.
 
강연은 영어로 진행됩니다.
 
 
세미나 참석을 원하시는 분은 세미나 시작 10분 전까지 입실해 주시기 바랍니다.
 
많은 참석 부탁드립니다. 감사합니다.
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Dear Colleagues,
 
There will be an Astronomy and Space Science 13th, 4:30 PM,  in Auditorium, Kyung Hee Astronomical Observatory.
Dr. Kazue Takahashi of APL Johns Hopkins Univ., U.S. will give a presentation about "Externally driven plasmaspheric ULF waves observed by the Van Allen Probes".
 
The language of the seminar will be English.
 
 
You are asked to join the seminar five to ten minutes before it starts. Your attendance will greatly be appreciated.
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Seminar Information
 
When: May 13th (Tues), 4:30 PM
 
Where: Auditorium, Kyung Hee Astronomical Observatory.
 
Speaker: Dr. Kazue Takahashi
 
Title : Externally driven plasmaspheric ULF waves observed by the Van Allen Probes
Abstract:
Van Allen Probes, with their low-inclination elliptical orbits with apogee at 5.8 Re, are ideal for studying ULF waves in the plasmasphere.
We analyze data acquired by these spacecraft on 8 November 2012 to gain new insight into quiet-time ULF waves in the plasmasphere.
The waves exhibit strong spectral power in the 5-40 mHz band outside L = 3 and include multiharmonic toroidal waves visible up to the 11th harmonic,
which is unprecedented in the plasmasphere. During this wave activity, the IMF cone angle was small, suggesting that the plasmaspheric waves were
driven by broadband compressional ULF waves originating in the foreshock region. This scenario is supported by the tailward propagation of the
compressional magnetic field perturbations that is determined using two-spacecraft phase delay analysis. The phase delay analysis, when applied to the
azimuthal component of the magnetic field, also reveals signatures of field line resonance that have not been reported in space. 
Finally, using the observed toroidal wave frequencies, we estimate the plasma mass density for 2.6-5.8.  By comparing the mass density with the electron
number density that is estimated from the spectrum of plasma waves, we find that the ion composition is dominated by H+.