Protons and alpha particles in field-aligned beams upstream of the bow shock
Protons and alpha particles in field-aligned beams upstream of the bow shock
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DOI：
10.1029/gl015i010p01153
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发表时间：
1988-09
影响因子：
5.2
通讯作者：
F. Ipavich;G. Gloeckler;D. Hamilton;L. Kistler;J. Gosling
中科院分区：
文献类型：
--
作者：
F. Ipavich;G. Gloeckler;D. Hamilton;L. Kistler;J. Gosling
我们报告了用AMPTECCE航天器在场对准光束（~ 10 keV/nuc）中对H+和He++离子的测量。质子束居群的密度约为太阳风密度的1%，且具有显著的热各向异性（ω⟂> ω∥），与前人的观测结果一致。发现光束密度与θBn角呈反相关。观测到的波束速度与“直接反射”模型相当一致，在“直接反射”模型中，一部分太阳风在地球的弓形激波处被反射和激发，但始终比磁鞘泄漏模型所预期的要大。光束中的He++离子与H+离子的速度大致相同，但He++与H+的密度比明显小于在太阳风中同时测量的密度比。我们的光束观测是在其他工作人员先前分析的几个时间间隔内获得的，他们使用来自同一艘航天器的数据，他们将上游离子流归因于磁层而不是弓弦激波的起源。
We report measurements of H+ and He++ ions in field-aligned beams (∼ 10 keV/nuc) made with the AMPTECCE spacecraft. The proton beam population has a density ≲ 1% of the solar wind density and a significant thermal anisotropy (ω⟂ > ω∥), in agreement with previous observations. The beam density is found to be anti-correlated with the angle θBn. The observed beam velocities are in reasonable agreement with the “direct reflection” model, in which a portion of the solar wind is reflected and energized at the earth's bow shock, but are consistently larger than expected from magnetosheath leakage models. The He++ ions in the beams have approximately the same velocity as the H+ ions, but the He++ to H+ density ratio is dramatically smaller than that measured simultaneously in the solar wind. Our beam observations were obtained during several of the time intervals previously analyzed by other workers, using data from the same spacecraft, who attributed the streaming upstream ions to magnetospheric rather than bow shock origin.