Solar wind stream evolution at large heliocentric distances: Experimental demonstration and the test of a model
Solar wind stream evolution at large heliocentric distances: Experimental demonstration and the test of a model
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大日心距离处的太阳风流演化：实验演示和模型测试
DOI：
10.1029/ja081i013p02111
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发表时间：
1976
影响因子：
--
通讯作者：
S. Bame
中科院分区：
文献类型：
--
作者：
J. Gosling;A. Hundhausen;S. Bame
本文详细比较了1973年6月1日至10月1日期间，IMP-7和先锋10号上的仪器在1.0AU和4.5AU观测到的太阳风流的速度-时间分布。这段时间包括先驱者10号与小行星7和太阳共同排列的一小段时间。这一比较提供了几个生动的例子，说明了太阳风中的气流变陡现象，以及伴随着正反激波对的形成，以及气流幅度随着日心距离的增加而逐渐衰减的现象。在某些方面，行星际介质似乎起到了‘低通滤光器’的作用；在1AU处存在的大幅度短波长速度结构在4.5AU处通常被抑制或不存在。采用一个简单的流传播模型，忽略了除激波界面外的所有耗散效应，定量地预测了在1AU处观测到的流结构的径向演化。在大多数情况下，该模式对先锋10号在4.5AU附近观测到的气流结构的大尺度特征提供了足够的描述，包括速度波动的幅度、在气流前沿存在的速度突变、到达4.5AU的时间、过滤掉短波结构以及速度-时间剖面的整体形状。该模型在预测河流前沿的详细结构方面做得不太好，例如，突然速度跳跃的幅度。在先锋10号与IMP 7和太阳共同排列的情况下，这种缺乏详细一致的情况无疑是由于模型假设绝热流动(激波除外)而忽略了磁力和非径向流动。在其他时候，上述原因加上太阳风流的非平稳性质，导致了缺乏详细的协议。(AIP)(更少)
A detailed comparison is made of the speed-time profiles of solar wind streams observed between June 1 and October 1, 1973, by instruments aboard Imp 7 at 1.0 AU and Pioneer 10 at 4.5 AU. This period includes a short interval when Pioneer 10 was coaligned with Imp 7 and the sun. The comparison provides several vivid illustrations of the phenomena of stream steepening in the solar wind with the attendant formation of forward-reverse shock pairs and the gradual decay of stream amplitudes with increasing heliocentric distance. In some respects the interplanetary medium appears to act like a 'low-pass filter'; large-amplitude short-wavelength speed structures present at 1 AU are generally subdued or absent at 4.5 AU. A simple fluid model of stream propagation which neglects all dissipation effects except those occurring at shock interfaces is employed to predict quantitatively the radial evolution of the stream structure observed at 1 AU. In most cases the model provides an adequate description of the large-scale features of the stream structure observed near 4.5 AU by Pioneer 10, including the amplitude of the speed fluctuations, the presence of abrupt jumps in speed at the leading edges of streams, the time of arrival at 4.5more » AU, the filtering out of short-wavelength structures, and the overall shape of speed-time profiles. The model does less well in predicting the detailed structure at the leading edges of streams, e.g., the amplitude of the abrupt speed jumps. In the case of coalignment of Pioneer 10 with Imp 7 and the sun this lack of detailed agreement undoubtedly arises from the model's assumption of adiabatic flow (except at shocks) and its neglect of magnetic forces and nonradial flow. For other times, the above reasons plus the nonstationary nature of solar wind streams contribute to the lack of detailed agreement. (AIP)« less
DOI：
--
发表时间：
2003
期刊：
Solar Wind Ten, AIP Conference Proceedings 679, AIP, New York, 1995, edited by M. Velli, R. Bruno and F. Malara
影响因子：
--
作者：
Yamashita;M.;M.Tokumaru;M.Kojima;Radial
通讯作者：
Radial