我们提出了一种新的方法的自动识别当前表(CS),代表了一个正式的视觉检查方法中采用的案例研究。通过分析行星际磁场(IMF)和等离子体参数的特征变化,通常可以用肉眼识别CS。已知的CS识别的视觉和半自动经验方法是准确的,但不允许CS属性的综合统计分析。现有的自动化方法部分解决了这个问题。同时,这些方法建议只分析IMF的变化及其方向。在我们的三参数经验方法中,我们采用太阳风等离子体和IMF参数来识别各种类型的CSs。使用IMF强度的导数、等离子体β和以一秒节奏取得的阿尔夫文速度VA与太阳风速度V的比率。我们发现,CS日变化率R与太阳风温度T相关,而不是与V相关,并且与动能密度和热能密度之和~ V2(N+5 N ')+10 T(N+ N')成正比,其中N '= 2 cm ^-3是太阳风密度N的背景水平。R的最大值与流/共转相互作用区和行星际物质抛射鞘有关。可在https://csdb.izmiran.ru上找到在1 AU处确定的CS的多年列表
英文摘要:
We propose a new method of the automated identification of current sheets (CSs) that represents a formalization of the visual inspection approach employed in case studies. CSs are often identified by eye via the analysis of characteristic changes in the interplanetary magnetic field (IMF) and plasma parameters. Known visual and semi-automated empirical methods of CS identification are exact but do not allow a comprehensive statistical analysis of CS properties. Existing automated methods partially solve this problem. Meanwhile, these methods suggest an analysis of variations of the IMF and its direction only. In our three-parameter empirical method, we employ both the solar wind plasma and IMF parameters to identify CSs of various types. Derivatives of the IMF strength, the plasma beta and the ratio of the Alfv'en speed VA to the solar wind speed V taken with the one-second cadence are used. We find that the CS daily rate R correlates with the solar wind temperature T rather than with V and is proportional to the sum of the kinetic and thermal energy density ~ V2(N+5N')+10T(N+N'), where N'=2cm^-3 is the background level of the solar wind density N. Maxima of R are associated with stream/corotating interaction regions and interplanetary mass ejection sheaths. A multiyear list of CSs identified at 1 AU can be found at https://csdb.izmiran.ru
Intermittency and electron heating in kinetic-Alfvén-wave turbulence
我们报告的分析和数值研究的低β等离子体中的亚离子尺度的湍流,侧重于波动和电子加热的光谱特性。在等温极限下,数值结果强烈支持Boldyrev & Perez(Astrophys. J. Lett. 758,L44(2012))以包括间歇性效应。当去除等温性的约束时(即,包括电子动力学物理),发现由于电子朗道阻尼,能谱变陡,这是通过电流片周围的对流非线性的局部减弱而实现的,并且经由速度-空间级联产生显著的能量耗散。使用厄米多项式表示来表达电子分布函数的速度空间依赖性,使我们能够获得分析,最低阶的解决方案的厄米矩的分布,这是证明了数值模拟。