Plasmoids in Saturn's magnetotail
Plasmoids in Saturn's magnetotail
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DOI：
10.1029/2007ja012626
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发表时间：
2008
影响因子：
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通讯作者：
T. Hill;M. Thomsen;M. Henderson;Robert L. Tokar;A. Coates;H. McAndrews;G. Lewis;D. Mitchell;
中科院分区：
文献类型：
--
作者：
T. Hill;M. Thomsen;M. Henderson;Robert L. Tokar;A. Coates;H. McAndrews;G. Lewis;D. Mitchell;
[1]土星磁尾中的等离子体团是由穿过尾电流片的磁场的通常向南分量的反转（向北转向）确定的。卡西尼号的磁力计已经发现了三个大的等离子体团，一个在当地时间0300附近，距离行星中心44 RS，两个在午夜附近，距离48-49 RS。(RS 60，300公里是土星的赤道半径。其中两个事件，特别是包括0300事件，正好与航天器的电流片交叉，从而提供了足够的等离子体通量，以确定离子成分和卡西尼等离子体光谱仪数据的速度矩。组成主要是由水的基团离子为主，表明内磁层源。流动是亚共旋和强烈的尾部，如预期的等离子体团。就在0300等离子体团的原位探测之前，磁层成像仪器观测到从土星和卡西尼号之间的中间位置发出的高能中性原子的爆发，可能是产生等离子体团的重连事件的标志。
[1] Plasmoids in Saturn's magnetotail are identified by a reversal (northward turning) of the normally southward component of the magnetic field across the tail current sheet. Three large plasmoids have been identified by the Cassini magnetometer, one near 0300 local time at a planet-centered distance of 44 RS and two near midnight at 48–49 RS. (RS ≈ 60,300 km is Saturn's equatorial radius.) Two of these events, including in particular the 0300 event, coincided with current-sheet crossings by the spacecraft and thus provided sufficient plasma fluxes to determine ion composition and velocity moments from Cassini Plasma Spectrometer data. The composition was largely dominated by water-group ions, indicating an inner-magnetosphere source. The flow was subcorotational and strongly tailward, as expected for a plasmoid. Just before the in situ detection of the 0300 plasmoid, the Magnetospheric Imaging Instrument observed an outburst of energetic neutral atoms emanating from a location midway between Saturn and Cassini, probably a signature of the reconnection event that spawned the plasmoid.