arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv physics/0409056physics.space-phastro-phnlin.CDphysics.data-anphysics.plasm-ph
收藏

行星际小尺度磁场起伏的概率分布函数

On the probability distribution function of small scale interplanetary magnetic field fluctuations

R. Bruno, B. Bavassano, V. Carbone, L. Primavera, F. Malara, L. Sorriso-Valvo, P. Veltri

摘要:

尽管有大量的论文致力于研究太阳风中的MHD湍流,但仍然有一些简单的问题从未得到充分解决,例如:a)我们真的知道磁场矢量方向在空间中是如何波动的吗?b)矢量本身的方向所遵循的统计量是什么?c)当风扩展到行星际空间时,统计数据会改变吗?更好地理解这些点可以帮助我们更好地描述行星际波动的性质,并可以为试图数值模拟MHD湍流的研究人员提供有用的提示。这项工作是在同一作者最近发表的一篇论文之后进行的。这项工作遵循最近的一篇论文提出的一些作者表明,这些波动可能类似于一种随机行走的截断利维飞行统计。然而,该文件中使用的统计数据有限,无法得出最后结论,只能提出推测性假设。在这项工作中,我们的目标是解决同样的问题,使用一个更强大的统计,一方面迫使我们不考虑速度波动,但另一方面,使我们能够建立更有信心的磁波动的管理统计的性质。此外,我们展示了如何在本统计分析中发现的那些特征相似的快速流的太阳风,定性恢复参数不稳定的数值模拟。这可能为解释上述问题提供另一种观点。

英文摘要:

In spite of a large number of papers dedicated to study MHD turbulence in the solar wind there are still some simple questions which have never been sufficiently addressed like: a)do we really know how the magnetic field vector orientation fluctuates in space? b) what is the statistics followed by the orientation of the vector itself? c) does the statistics change as the wind expands into the interplanetary space? A better understanding of these points can help us to better characterize the nature of interplanetary fluctuations and can provide useful hints to investigators who try to numerically simulate MHD turbulence. This work follows a recent paper presented by the same authors. This work follows a recent paper presented by some of the authors which shows that these fluctuations might resemble a sort of random walk governed by a Truncated Leevy Flight statistics. However, the limited statistics used in that paper did not allow final conclusions but only speculative hypotheses. In this work we aim to address the same problem using a more robust statistics which on one hand forces us not to consider velocity fluctuations but, on the other hand allows us to establish the nature of the governing statistics of magnetic fluctuations with more confidence. In addition, we show how features similar to those found in the present statistical analysis for the fast speed streams of solar wind, are qualitatively recovered in numerical simulations of the parametric instability. This might offer an alternative viewpoint for interpreting the questions raised above.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑