COMET GIACOBINI-ZINNER - PLASMA DESCRIPTION
COMET GIACOBINI-ZINNER - PLASMA DESCRIPTION
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DOI：
10.1126/science.232.4748.356
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发表时间：
1986-04-18
期刊：
影响因子：
56.9
通讯作者：
ZWICKL, RD
中科院分区：
文献类型：
--
作者：
BAME, SJ;ANDERSON, RC;ZWICKL, RD
1985年9月11日，国际彗星探测器（ICE）航天器上的洛斯阿拉莫斯等离子体电子实验观测到了太阳风和贾科比尼-津纳彗星之间的强烈相互作用。当ICE从南面接近彗星核后7800公里的拦截点并向北后退时，观测到了彗星造成的上游现象。测量了来自彗星的增强的电子热通量以及几乎连续的电子密度波动的周期。这些效应分别与在彗星相互作用区观察到的强电子加热和太阳风对彗星离子的拾取有关。当ICE进入和退出太阳风与彗星环境相互作用最强的区域时，没有发现传统弓形激波的证据。这个强相互作用区的外部是一个过渡区，在这个过渡区中，太阳风等离子体被加热、压缩和减速。在过渡区的内边界内是一个鞘层，鞘层中包裹着一个冷的中间彗发。在过渡区和鞘中，观察到小规模的密度增强。这些密度峰值可能是由于彗星离子拾取或ICE通过彗星射线结构的不稳定性。在冷的中间彗发的中心，发现了一个狭窄的高密度等离子体核心，可能是正在形成的等离子体尾部。在某些方面，这个尾部可以与地球磁尾的等离子体片和金星尾部的电流片相比较。在彗星上探测到的双瓣磁拓扑中预计会出现这种配置，这可能是由理论上预期的行星际磁场在其电离层周围的覆盖造成的。
A strong interaction between the solar wind and comet Giacobini-Zinner was observed oh 11 September 1985 with the Los Alamos plasma electron experiment on the International Cometary Explorer (ICE) spacecraft. As ICE approached an intercept point 7800 kilometers behind the nucleus from the south and receded to the north, upstream phenomena due to the comet were observed. Periods of enhanced electron heat flux from the comet as well as almost continuous electron density fluctuations were measured. These effects are related to the strong electron heating observed in the cometary interaction region and to cometary ion pickup by the solar wind, respectively. No evidence for a conventional bow shock was found as ICE entered and exited the regions of strongest interaction of the solar wind with the cometary environment. The outer extent of this strong interaction zone was a transition region in which the solar wind plasma was heated, compressed, and slowed. Inside the inner boundary of the transition region was a sheath that enclosed a cold intermediate coma. In the transition region and sheath, small-scale enhancements in density were observed. These density spikes may be due to an instability associated with cometary ion pickup or to the passage of ICE through cometary ray structures. In the center of the cold intermediate coma a narrow, high-density core of plasma, presumably the developing plasma tail, was found. In some ways this tail can be compared to the plasma sheet in Earth's magnetotail and to the current sheet in the tail at Venus. This type of configuration is expected in the double-lobe magnetic topology detected at the comet, possibly caused by the theoretically expected draping of the interplanetary magnetic field around its ionosphere.