Longitudinal development of a substorm brightening arc
Longitudinal development of a substorm brightening arc
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DOI：
10.5194/angeo-27-1935-2009
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发表时间：
2009-05
影响因子：
1.9
通讯作者：
K. Shiokawa;A. Ieda;A. Nakajima;K. Sakaguchi;R. Nomura;T. Aslaksen;M. Greffen;E. Spanswick;E. Donovan;S. Mende;J. Mcfadden;K. Glassmeier;V. Angelopoulos;Y. Miyashita
中科院分区：
文献类型：
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作者：
K. Shiokawa;A. Ieda;A. Nakajima;K. Sakaguchi;R. Nomura;T. Aslaksen;M. Greffen;E. Spanswick;E. Donovan;S. Mende;J. Mcfadden;K. Glassmeier;V. Angelopoulos;Y. Miyashita
抽象的。我们在2008年1月10日08：13 UT的Gillam（磁纬：65.6°）提供了亚暴初始增亮弧纵向（向东）延伸的同步THEMIS-地面观测结果。弧向东延伸的速度约为2.7 km/s。延伸发生在非常接近纵向分离的THEMIS E和D卫星在~12 RE的足迹。THEMIS卫星观测到了场的偶极化、微弱的向地流动和压力的增加，这些流动以约50 km/s的速度从E向东传播到D。THEMIS A卫星位于THEMIS E地球方向1.6 RE处，观测到了双极化期间和之后的波动磁场。THEMIS E/D观测表明，亚暴发生时增亮弧的纵向延伸是由近地等离子体片中产生场偶极和沿经度传播的压力增加的向地流动制动过程引起的。
Abstract. We present simultaneous THEMIS-ground observations of longitudinal (eastward) extension of a substorm initial-brightening arc at Gillam (magnetic latitude: 65.6°) at 08:13 UT on 10 January 2008. The speed of the eastward arc extension was ~2.7 km/s. The extension took place very close to the footprints of the longitudinally separated THEMIS E and D satellites at ~12 RE. The THEMIS satellites observed field dipolarization, weak earthward flow, and pressure increase, which propagated eastward from E to D at a speed of ~50 km/s. The THEMIS A satellite, located at 1.6 RE earthward of THEMIS E, observed fluctuating magnetic field during and after the dipolarization. The THEMIS E/D observations suggest that the longitudinal extension of the brightening arc at substorm onset is caused by earthward flow braking processes which produce field dipolarization and pressure increase propagating in longitude in the near-earth plasma sheet.