Evidence for magnetic field reconnection at the Earth's magnetopause
Evidence for magnetic field reconnection at the Earth's magnetopause
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DOI：
10.1029/ja086ia12p10049
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发表时间：
1981-11
影响因子：
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通讯作者：
B. Sonnerup;G. Paschmann;I. Papamastorakis;N. Sckopke;G. Haerendel;S. Bame;J. Asbridge;J. Gosling;C. Russell
中科院分区：
文献类型：
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作者：
B. Sonnerup;G. Paschmann;I. Papamastorakis;N. Sckopke;G. Haerendel;S. Bame;J. Asbridge;J. Gosling;C. Russell
已经确定ISEE卫星11次通过正面地球磁层顶（当地时间0900-1700; GSM纬度2-43°N），其中磁层顶和边界层中的等离子体速度远大于磁鞘中的速度。本文探讨的等离子体流，磁场和高能粒子通量在这些地区的性质，以确定是否可以解释的磁场重联的速度增强。主要的问题是，在磁层顶或边界层中的一点与相邻磁鞘中的一个参考点之间观测到的切向等离子体速度差Δv，是否具有由磁层顶中的麦克斯韦应力产生的方向和大小Δ v理论，假设磁鞘等离子体穿过边界移动。除符号外，Δvtheory与法向磁场分量Bn和流动分量Bn无关。在这11个案例中，|Δv|/|Δv|理论值在0.6-1.2的范围内，复合平均值为0.8。平均角度误差为0）。从磁数据的最小方差分析获得的Bn值大多是不好确定的，但在一般情况下，他们的迹象是一致的等离子体的结果。穿过磁层顶的气流速度也很难确定，但正如预期的那样，它有一个负的（向内的）复合平均值。在几种情况下，在磁层顶之外但邻近磁层顶的地方观测到具有适当的流动各向异性的高能磁层粒子，在一种情况下观测到反射磁鞘粒子。所有这些结果都支持重连假说。高能粒子也被用来识别外分界面。在一种情况下，可以从它相对于磁层顶的位置得出结论，重联地点在赤道面附近，而不是在尖点。磁层顶切向电场的范围为0.4-2.8 mV/m。
Eleven passes of the ISEE satellites through the frontside terrestrial magnetopause (local time 0900–1700; GSM latitude 2–43°N) have been identified, where the plasma velocity in the magnetopause and boundary layer was substantially larger than it was in the magnetosheath. This paper examines the nature of the plasma flow, magnetic field, and energetic particle fluxes in these regions, with a view to determining whether the velocity enhancements can be explained by magnetic-field reconnection. The principal question is whether the observed difference in tangential plasma velocity Δv between a point in the magnetopause or boundary layer and a reference point in the adjacent magnetosheath, had the direction and magnitude Δvtheory produced by the Maxwell stresses in the magnetopause, assuming that the magnetosheath plasma moved across that boundary. Except for its sign, Δvtheory is shown to be independent of the normal magnetic field component Bn and flow component υn. For the 11 cases, the average ratio |Δv|/|Δv|theory was in the range 0.6–1.2, with a composite average of 0.8. The average angular error was 0). The Bn values obtained from minimum variance analysis of the magnetic data were mostly poorly determined, but in general their signs were consistent with the plasma results. The flow velocity across the magnetopause was also poorly determined but it had a negative (inward) composite average as expected. In several cases energetic magnetospheric particles with the proper flow anisotropy and, in one case, reflected magnetosheath particles, were observed outside but adjacent to the magnetopause. All of these results support the reconnection hypothesis. The energetic particles were also used to identify the outer separatrix surface. In one case it was possible to conclude from its location relative to the magnetopause that the reconnection site was in the vicinity of the equatorial plane and not in the cusp. The electric field tangential to the magnetopause is inferred to be in the range 0.4–2.8 mV/m.