DOI: 10.1029/2017JA024885
Scopus记录号: 2-s2.0-85046830964
论文题名: Field-Aligned Currents in Saturn's Nightside Magnetosphere: Subcorotation and Planetary Period Oscillation Components During Northern Spring
作者: Bradley T.J. ; Cowley S.W.H. ; Provan G. ; Hunt G.J. ; Bunce E.J. ; Wharton S.J. ; Alexeev I.I. ; Belenkaya E.S. ; Kalegaev V.V. ; Dougherty M.K.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 5 起始页码: 3602
结束页码: 3636
语种: 英语
英文关键词: aurora
; field-aligned currents
; magnetosphere
; Saturn
英文摘要: We newly analyze Cassini magnetic field data from the 2012/2013 Saturn northern spring interval of highly inclined orbits and compare them with similar data from late southern summer in 2008, thus providing unique information on the seasonality of the currents that couple momentum between Saturn's ionosphere and magnetosphere. Inferred meridional ionospheric currents in both cases consist of a steady component related to plasma subcorotation, together with the rotating current systems of the northern and southern planetary period oscillations (PPOs). Subcorotation currents during the two intervals show opposite north-south polar region asymmetries, with strong equatorward currents flowing in the summer hemispheres but only weak currents flowing to within a few degrees of the open-closed boundary (OCB) in the winter hemispheres, inferred due to weak polar ionospheric conductivities. Currents peak at ~1 MA rad−1 in both hemispheres just equatorward of the open-closed boundary, associated with total downward polar currents ~6 MA, then fall across the narrow auroral upward current region to small values at subauroral latitudes. PPO-related currents have a similar form in both summer and winter with principal upward and downward field-aligned currents peaking at ~1.25 MA rad−1 being essentially collocated with the auroral upward current and approximately equal in strength. Though northern and southern PPO currents were approximately equal during both intervals, the currents in both hemispheres were dual modulated by both systems during 2012/2013, with approximately half the main current closing in the opposite ionosphere and half cross field in the magnetosphere, while only the northern hemisphere currents were similarly dual modulated in 2008. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113977
Appears in Collections: 气候减缓与适应
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作者单位: Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom; Blackett Laboratory, Imperial College London, London, United Kingdom; Federal State Budget Educational Institution of Higher Education M. V. Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow, Russian Federation
Recommended Citation:
Bradley T.J.,Cowley S.W.H.,Provan G.,et al. Field-Aligned Currents in Saturn's Nightside Magnetosphere: Subcorotation and Planetary Period Oscillation Components During Northern Spring[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(5)