DOI: 10.1002/2016GL069601
论文题名: Electric fields associated with small-scale magnetic holes in the plasma sheet: Evidence for electron currents
作者: Goodrich K.A. ; Ergun R.E. ; Stawarz J.E.
刊名: Geophysical Research Letters
ISSN: 0094-9673
EISSN: 1944-9404
出版年: 2016
卷: 43, 期: 12 起始页码: 6044
结束页码: 6050
语种: 英语
英文关键词: Magnetic Holes
Scopus关键词: Electric drives
; Electric fields
; Ions
; Magnetism
; Magnetohydrodynamics
; Plasma sheaths
; Pressure gradient
; Bursty bulk flow
; Current layers
; Electron currents
; Ion pressure gradients
; Larmor radii
; Magnetic Holes
; Negative potential
; Plasma sheet
; Magnetoplasma
英文摘要: We report observations of magnetic holes (MHs) in the near-Earth (8 RE to 12 RE) plasma sheet that have physical sizes perpendicular to the magnetic field (B) on the order of the ion Larmor radius (ρi) and, more importantly, have current layers less than ρi in thickness. Small-scale MHs can have >90% depletion in |B| and are commonly associated with the braking of bursty bulk flow events. The generation of MHs is often attributed to magnetohydrodynamic (MHD) instabilities, which requires a size greater than ρi; the depletion in |B| is from an ion current consistent with a pressure gradient. Electric field (E) observations indicate a negative potential inside of small-scale MHs that creates an outward E at the boundary, which drives an E × B electron current in a thin layer. These observations indicate that a Hall electron current is primarily responsible for the depletion of |B| in small-scale magnetic holes, rather than the ion pressure gradient. ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977502242&doi=10.1002%2f2016GL069601&partnerID=40&md5=51441c65c95ba5bc0bc5bb2e13d6aa7b
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/10636
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, CO, United States
Recommended Citation:
Goodrich K.A.,Ergun R.E.,Stawarz J.E.. Electric fields associated with small-scale magnetic holes in the plasma sheet: Evidence for electron currents[J]. Geophysical Research Letters,2016-01-01,43(12).