论文标题
关于膨胀太阳风中Alfvénic折返的特性：Parker螺旋的影响
On the properties of Alfvénic switchbacks in the expanding solar wind: the influence of the Parker spiral
论文作者
论文摘要
折返 - 太阳风的磁场的快速偏转 - 已经引起了对关键机制加热电晕并加速太阳风的关键机制的引起巨大兴趣。在这种情况下，换回形成和演变理论的重要任务是了解其可观察到的区分特征，从而可以使用航天器数据详细评估它们。在这里，我们通过研究Parker螺旋的影响对扩展的等离子体中Alfvénic折返的影响来实现这一目标。使用基于一维球形极化（恒定场宽度）alfvén波的物理学的简单分析参数，我们发现，通过控制波浪的倾斜度，帕克螺旋螺旋强烈影响换回特性。令人惊讶的是，尽管在存在下，帕克螺旋可以显着增强切换的形成，尽管归一化的波幅度幅度较慢。此外，折返变得强烈不对称：大型折返优先涉及parker螺旋的磁场旋转（切向偏转），而不是垂直（正常）旋转，并且这种偏转强烈“切向倾斜”，这意味着“始终涉及相同方向的野外旋转（朝着朝外的方向），以朝外（朝外），以朝外的方向旋转。在同伴纸中，我们表明这些特性也出现在带有各种警告的湍流3-D场中。这些结果表明，在假设折返的特定特征可用于推断低电晕的特性时，需要进行大量护理。由于膨胀与球形极化，无差异磁场之间的相互作用，不对称和非平凡相关性可以随着折返的传播而发展。
Switchbacks -- rapid, large deflections of the solar wind's magnetic field -- have generated significant interest as possible signatures of the key mechanisms that heat the corona and accelerate the solar wind. In this context, an important task for theories of switchback formation and evolution is to understand their observable distinguishing features, allowing them to be assessed in detail using spacecraft data. Here, we work towards this goal by studying the influence of the Parker spiral on the evolution of Alfvénic switchbacks in an expanding plasma. Using simple analytic arguments based on the physics of one-dimensional spherically polarized (constant-field-magnitude) Alfvén waves, we find that, by controlling the wave's obliquity, a Parker spiral strongly impacts switchback properties. Surprisingly, the Parker spiral can significantly enhance switchback formation, despite normalized wave amplitudes growing more slowly in its presence. In addition, switchbacks become strongly asymmetric: large switchbacks preferentially involve magnetic-field rotation in the plane of the Parker spiral (tangential deflections) rather than perpendicular (normal) rotations, and such deflections are strongly "tangentially skewed," meaning switchbacks always involve field rotations in the same direction (towards the positive-radial direction for an outwards mean field). In a companion paper, we show that these properties also occur in turbulent 3-D fields with switchbacks, with various caveats. These results demonstrate that substantial care is needed in assuming that specific features of switchbacks can be used to infer properties of the low corona; asymmetries and nontrivial correlations can develop as switchbacks propagate due to the interplay between expansion and spherically polarized, divergence-free magnetic fields.
