论文标题
内部气球中离子尺度上的相干事件:\ textit {parker solar探针}在第一次相遇期间观察
Coherent events at ion scales in the inner Heliosphere: \textit{Parker Solar Probe} observations during the first Encounter
论文作者
论文摘要
\ textit {Parker Solar Probe}在其第一个圆锥体中,它嵌入了高度alfvénic的慢速流中,表明了强大的磁场偏转的存在,即折返。在这里,我们分别以三个间隔研究离子尺度周围的湍流磁波动,其特征是不同的换回活动,这些换回活动由磁场径向分量的行为($ b_r $)确定。 \ textIt {quet}($ b_r $没有显示显着的波动),\ textit {feff}($ b_r $具有强大的波动,但没有反转)和\ textit {strong}($ b_r $具有完整的反向)时期也显示出与离子数量和alfvvenicity的不同行为。但是,光谱分析表明,每个流的特征是惯性范围内典型的kolmogorov/kraichnan幂定律,然后在特征离子尺度周围发生断裂。该频率范围的特征是强烈的间歇性活性,存在非压缩相干结构(例如电流板和类似涡流的结构)和波数据包,被识别为离子回旋体模式。尽管在三个时期都检测到了所有这些间歇性事件,但它们的影响都不同。当前的纸在\ textit {strong}时期是占主导地位的,波数据包是\ textit {letim}间隔中最常见的;而在\ textit {feal}时期,观察到涡流和波数据包的混合物。这项工作提供了对无碰撞等离子体中的加热问题的见解,在新的太阳能任务中拟合,尤其是对于\ textit {太阳轨道},这将允许准确的磁连通性分析,以将不同间歇性事件的存在链接到源区域。
\textit{Parker Solar Probe} has shown the ubiquitous presence of strong magnetic field deflections, namely switchbacks, during its first perihelion where it was embedded in a highly Alfvénic slow stream. Here, we study the turbulent magnetic fluctuations around ion scales in three intervals characterized by a different switchback activity, identified by the behaviour of the magnetic field radial component, $B_r$. \textit{Quiet} ($B_r$ does not show significant fluctuations), \textit{weak} ($B_r$ has strong fluctuations but no reversals) and \textit{strong} ($B_r$ has full reversals) periods show a different behaviour also for ion quantities and Alfvénicity. However, the spectral analysis shows that each stream is characterized by the typical Kolmogorov/Kraichnan power law in the inertial range, followed by a break around the characteristic ion scales. This frequency range is characterized by strong intermittent activity, with the presence of non-compressive coherent structures, such as current sheets and vortex-like structures, and wave packets, identified as ion cyclotron modes. Although, all these intermittent events have been detected in the three periods, they have a different influence in each of them. Current sheets are dominant in the \textit{strong} period, wave packets are the most common in the \textit{quiet} interval; while, in the \textit{weak} period, a mixture of vortices and wave packets is observed. This work provides an insight into the heating problem in collisionless plasmas, fitting in the context of the new solar missions, and, especially for \textit{Solar Orbiter}, which will allow an accurate magnetic connectivity analysis, to link the presence of different intermittent events to the source region.