THE MORPHOLOGY OF DAYSIDE BIRKELAND CURRENTS

被引:21
作者
SAUNDERS, MA
机构
[1] The Blackett Laboratory, Imperial College of Science, Technology and Medicine, London
来源
JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS | 1992年 / 54卷 / 3-4期
关键词
D O I
10.1016/0021-9169(92)90024-F
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Intense (10(5) A) electric currents flow into and from the Earth's two polar ionospheres near magnetic noon, These currents, called Birkeland or magnetic field-aligned currents, are the agent by which momentum couples from the flowing solar wind plasma to drive plasma motions in the high latitude ionosphere. Coupling is strongest when the interplanetary magnetic field (IMF) has a southward component and when this occurs there exist two principal regions of Birkeland current near magnetic noon called the region 1 and the cusp systems. We present a simple model bringing theoretical order to the many patterns proposed previously for the morphology of these dayside Birkeland currents as observed by orbiting satellites in the topside polar ionosphere. Specifically we show that the cusp Birkeland current system is not a latitudinally separate region but is instead the extension in longitude of the region 1 Birkeland current from either dawn or dusk; which particular one depends on the sign of the east-west (Y) component of the IMF. The presence of an IMF Y-component therefore leads to two region 1 current systems near magnetic noon, with the poleward one being that previously called the 'cusp' system.
引用
收藏
页码:457 / 461
页数:5
相关论文
共 23 条
[1]   BIRKELAND CURRENTS AND CHARGED-PARTICLES IN THE HIGH-LATITUDE PRENOON REGION - A NEW INTERPRETATION [J].
BYTHROW, PF ;
POTEMRA, TA ;
ERLANDSON, RE ;
ZANETTI, LJ ;
KLUMPAR, DM .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1988, 93 (A9) :9791-9803
[2]  
Chapman S., 1940, GEOMAGNETISM
[3]   FIELD-ALIGNED CURRENTS AND ELECTRIC-FIELDS OBSERVED IN THE REGION OF THE DAYSIDE CUSP [J].
DOYLE, MA ;
RICH, FJ ;
BURKE, WJ ;
SMIDDY, M .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1981, 86 (NA7) :5656-5664
[4]   STUDIES OF CONJUGATE PLASMA CONVECTION IN THE VICINITY OF THE HARANG DISCONTINUITY [J].
DUDENEY, JR ;
RODGER, AS ;
PINNOCK, M ;
RUOHONIEMI, JM ;
BAKER, KB ;
GREENWALD, RA .
JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS, 1991, 53 (3-4) :249-263
[5]   IMF BY DEPENDENCE OF REGION-1 BIRKELAND CURRENTS NEAR NOON [J].
ERLANDSON, RE ;
ZANETTI, LJ ;
POTEMRA, TA ;
BYTHROW, PF ;
LUNDIN, R .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1988, 93 (A9) :9804-9814
[6]  
GALPERIN YI, 1978, J GEOPHYS RES-SPACE, V83, P4265, DOI 10.1029/JA083iA09p04265
[7]   SIMULTANEOUS CONJUGATE OBSERVATIONS OF DYNAMIC VARIATIONS IN HIGH-LATITUDE DAYSIDE CONVECTION DUE TO CHANGES IN IMF-BY [J].
GREENWALD, RA ;
BAKER, KB ;
RUOHONIEMI, JM ;
DUDENEY, JR ;
PINNOCK, M ;
MATTIN, N ;
LEONARD, JM ;
LEPPING, RP .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1990, 95 (A6) :8057-8072
[8]  
HEELIS RA, 1979, ESA SP148, P175
[9]   EMPIRICAL HIGH-LATITUDE ELECTRIC-FIELD MODELS [J].
HEPPNER, JP ;
MAYNARD, NC .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1987, 92 (A5) :4467-4489
[10]   FIELD-ALIGNED CURRENTS IN DAYSIDE CUSP OBSERVED BY TRIAD [J].
IIJIMA, T ;
POTEMRA, TA .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1976, 81 (34) :5971-5979