Propagation of sudden disturbances through a nonhomogeneous solar wind
Propagation of sudden disturbances through a nonhomogeneous solar wind
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通过非均匀太阳风传播突然扰动
DOI：
10.1029/ja079i025p03726
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发表时间：
1974
期刊：
影响因子：
--
通讯作者：
R. E. Wellck
中科院分区：
文献类型：
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作者：
J. Hirshberg;Y. Nakagawa;R. E. Wellck
在太阳耀斑扰动通过太阳风传播的早期研究中，这个问题被视为球对称的。然而，在1天文单位的典型行星际条件是由一系列高速流主导的，每个流之前都有一个密度峰值。先前的计算表明，速度和密度的不均匀性对传输时间和传播扰动的强度有重要影响。其他工作人员在数值上研究了流对冲击传播的影响，这些冲击在整个传播过程中被限制在1 AU以内。然而，星际激波在整个传播过程中保持强烈的约束是不现实的，因为在1天文单位的空间观测到的激波通常具有低或中等马赫数。我们在这里报告一个计算，其中一个突然的球对称扰动在30 Rs被引入，并允许通过太阳风包含一个速度流传播。当扰动传播时，对扰动强度的演变没有任何限制。在1au处，扰动在流的低速部分仍然很强，并且从太阳传播的速度相对较慢。在高速区，扰动达到1 AU的速度更快，但强度较弱。在密度峰附近，在1au处看到的扰动形式是高度扭曲的。换句话说，计算出的1天文单位扰动的过境时间、强度和形式明显取决于观测到的流中的位置。
In the earliest studies of the propagation of solar flare disturbances through the solar wind the problem was treated as being spherically symmetric. However, typically interplanetary conditions at 1 AU are dominated by a series of high-velocity streams, each preceded by a density peak. Earlier calculations have indicated that velocity and density inhomogeneities have important effects on transit times and strengths of propagating disturbances. Other workers have numerically investigated the effect of streams on the propagation of shocks confined to remain strong throughout the propagation to 1 AU. However, the constraint that the interplanetary shock remain strong throughout its propagation is unrealistic, since the shocks observed in space at 1 AU often have low or intermediate Mach numbers. We here report on a calculation in which a sudden spherically symmetric disturbance is introduced at 30 Rs and allowed to propagate through a solar wind containing a velocity stream. No restriction is made on the evolution of the strength of the disturbance as it propagates. It was found that at 1 AU the disturbance remained strong in the low-velocity part of the stream and that it propagated from the sun relatively slowly. In the high-velocity region the disturbance reached 1 AU more rapidly but was weaker. Near the density peak the form of the disturbance seen at 1 AU was highly distorted. In other words, it is shown that the calculated transit time, strength, and form of the disturbance at 1 AU depend markedly on the position within the stream at which it is observed.
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