DOI: 10.1002/2014GL059383
论文题名: Relativistic electron acceleration during high-intensity, long-duration, continuous AE activity (HILDCAA) events: Solar cycle phase dependences
作者: Hajra R. ; Tsurutani B.T. ; Echer E. ; Gonzalez W.D.
刊名: Geophysical Research Letters
ISSN: 0094-10219
EISSN: 1944-9950
出版年: 2014
卷: 41, 期: 6 起始页码: 1876
结束页码: 1881
语种: 英语
英文关键词: Alfvén waves
; chorus waves
; high-speed streams
; HILDCAAs
; magnetospheric relativistic electrons
; solar cycle phases
Scopus关键词: Electrons
; Geomagnetism
; Magnetosphere
; Solar wind
; Wind
; Chorus waves
; high-speed streams
; HILDCAAs
; N-waves
; Relativistic electron
; Solar cycle
; Solar energy
; electron
; geomagnetic field
; magnetic field
; magnetosphere
; solar cycle
; solar wind
; wind velocity
英文摘要: High-intensity, long-duration, continuous AE activity (HILDCAA) intervals during solar cycle 23 (1995-2008) have been studied by a superposed epoch analysis. It was found that HILDCAA intervals order the solar wind velocity, temperature and density (characteristic of high-speed solar wind intervals), the polar cap potential, and various other geomagnetic indices well. The interplanetary magnetic field Bz is generally negative, and the Newell solar wind coupling function is high during HILDCAA events. The HILDCAA intervals are well correlated with an enhancement of magnetospheric relativistic (E > 2 MeV) electron fluxes observed at geosynchronous orbit with a delay of ∼1.5 days from the onset of the HILDCAAs. The response of the energetic electrons to HILDCAAs is found to vary with solar cycle phase. The initial electron fluxes are lower for events occurring during the ascending and solar maximum (AMAX) phases than for events occurring during the descending and solar minimum (DMIN) phases. The flux increases for the DMIN phase events are >50% larger than for the AMAX phase events. Although the solar wind speeds during the DMIN phases were slightly higher and lasted longer than during the AMAX phases, no other significant solar wind differences were noted. It is concluded that electrons are accelerated to relativistic energies most often and most efficiently during the DMIN phases of the solar cycle. We propose two possible solar UV mechanisms to explain this solar cycle effect. © 2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898881386&doi=10.1002%2f2014GL059383&partnerID=40&md5=42a25c275ba130b65262c34246297494
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7483
Appears in Collections: 气候减缓与适应
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作者单位: Instituto Nacional de Pesquisas Espaciais (INPE), São José Dos Campos, São Paulo, Brazil
Recommended Citation:
Hajra R.,Tsurutani B.T.,Echer E.,et al. Relativistic electron acceleration during high-intensity, long-duration, continuous AE activity (HILDCAA) events: Solar cycle phase dependences[J]. Geophysical Research Letters,2014-01-01,41(6).