Vertical Current Density Structure of Saturn's Equatorial Current Sheet

被引:0
作者
Martin, C. J. [1 ]
Arridge, C. S. [1 ]
Case, N. A. [1 ]
Ray, L. C. [1 ]
机构
[1] Univ Lancaster, Phys Dept, Lancaster, England
关键词
BIFURCATED CURRENT SHEET; THIN CURRENT SHEETS; TAIL CURRENT SHEET; MAGNETIC-FIELD; PLASMA; RECONNECTION; MODEL;
D O I
10.1029/2019JA026767
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Routine spacecraft encounters with the Saturn current sheet due to the passage of aperiodic waves provide the opportunity to analyze the current sheet structure. The current density is expected to peak where the field strength reaches a minimum if approximated as a Harris current sheet. However, in Earth's magnetotail this is not always the case as the sheet is sometimes bifurcated (having two or more maxima in the current density). We utilize measurements of Saturn's magnetic field to estimate the current density during crossings of the current sheet by time differentiating the B-a component of the field in a current sheet coordinate system, where B-a is perpendicular to both the current and current sheet normal. This is then averaged and organized by the magnitude of B-a. Using this method, we can identify a classical Harris-style or bifurcated current sheet as a peak at the center or two distinct maxima on either side of B-a = 0, respectively. We find that around 10% of current sheet profiles exhibit a bifurcated current sheet signature, which is substantially lower than an similar to 25% occurrence rate at Earth.
引用
收藏
页码:5097 / 5106
页数:10
相关论文
共 52 条
[1]   MAGNETIC-FIELD OF SATURN - PIONEER-11 OBSERVATIONS [J].
ACUNA, MH ;
NESS, NF .
SCIENCE, 1980, 207 (4429) :444-446
[2]   Sources of Local Time Asymmetries in Magnetodiscs [J].
Arridge, C. S. ;
Kane, M. ;
Sergis, N. ;
Khurana, K. K. ;
Jackman, C. M. .
SPACE SCIENCE REVIEWS, 2015, 187 (1-4) :301-333
[3]   Periodic motion of Saturn's nightside plasma sheet [J].
Arridge, C. S. ;
Andre, N. ;
Khurana, K. K. ;
Russell, C. T. ;
Cowley, S. W. H. ;
Provan, G. ;
Andrews, D. J. ;
Jackman, C. M. ;
Coates, A. J. ;
Sittler, E. C. ;
Dougherty, M. K. ;
Young, D. T. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2011, 116
[4]   Mass of Saturn's magnetodisc:: Cassini observations [J].
Arridge, C. S. ;
Russell, C. T. ;
Khurana, K. K. ;
Achilleos, N. ;
Andre, N. ;
Rymer, A. M. ;
Dougherty, M. K. ;
Coates, A. J. .
GEOPHYSICAL RESEARCH LETTERS, 2007, 34 (09)
[5]   Saturn's magnetodisc current sheet [J].
Arridge, C. S. ;
Russell, C. T. ;
Khurana, K. K. ;
Achilleos, N. ;
Cowley, S. W. H. ;
Dougherty, M. K. ;
Southwood, D. J. ;
Bunce, E. J. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2008, 113 (A4)
[6]   Warping of Saturn's magnetospheric and magnetotail current sheets [J].
Arridge, C. S. ;
Khurana, K. K. ;
Russell, C. T. ;
Southwood, D. J. ;
Achilleos, N. ;
Dougherty, M. K. ;
Coates, A. J. ;
Leinweber, H. K. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2008, 113 (A8)
[7]   How typical are atypical current sheets? -: art. no. L03108 [J].
Asano, Y ;
Nakamura, R ;
Baumjohann, W ;
Runov, A ;
Vörös, Z ;
Volwerk, M ;
Zhang, TL ;
Balogh, A ;
Klecker, B ;
Réme, H .
GEOPHYSICAL RESEARCH LETTERS, 2005, 32 (03) :1-4
[8]   Forced reconnection in the near magnetotail: Onset and energy conversion in PIC and MHD simulations [J].
Birn, J. ;
Hesse, M. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2014, 119 (01) :290-309
[9]   Model of bifurcated current sheets in the Earth's magnetotail: Equilibrium and stability [J].
Camporeale, E ;
Lapenta, G .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2005, 110 (A7)
[10]   Role of oxygen ions in the formation of a bifurcated current sheet in the magnetotail [J].
Dalena, S. ;
Greco, A. ;
Zimbardo, G. ;
Veltri, P. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2010, 115