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首页> 外文学位 >Theory of three-dimensional interchange reconnection and the dynamic evolution of the global solar coronal magnetic field structure: A mechanism for the origin and generation of the slow solar wind.
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Theory of three-dimensional interchange reconnection and the dynamic evolution of the global solar coronal magnetic field structure: A mechanism for the origin and generation of the slow solar wind.

机译：三维互换重新连接理论和全球太阳日冕磁场结构的动态演化：慢速太阳风的起源和产生机制。

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摘要

To understand the evolution of the solar corona and the generation of the solar wind, it is necessary to understand the structure and dynamics of the coronal magnetic field. Phenomenologically-based "quasi-steady" models have been developed under the assumption that the corona evolves as a time series of force-free equilibrium states determined by the normal-flux distribution at the photosphere. These models are successful at predicting the overall field polarity, global magnetic structures, and position of the heliospheric current sheet. However, the quasi-steady models cannot account for the observed bi-modal flow structure of the solar wind, nor several heliospheric observations with implications for the dynamics of the magnetic field. Motivated by these limitations, several researchers have proposed a fundamentally different paradigm for the evolution of the corona, the so-called interchange model. Based on the interchange reconnection (IR) process, this model predicts a structure for the coronal magnetic field which substantially differs from the quasi-steady view. Strictly speaking, IR describes three-dimensional (3D) null point reconnection, in which closed bipolar flux reconnects with coronal hole flux opening into the heliosphere. More generally, the 3D null point reconnection mechanism is a direct consequence of the nested multi-polar field structure which occurs ubiquitously throughout the entire corona. This dissertation aims to rigorously investigate the 3D null point reconnection mechanism and the consequences thereof on the coronal environment. To that end, we present several related simulations that examine current sheet formation and stability, as well as the consequences of this type of reconnection on the structure and dynamics of the global magnetic field. We show the field topology remains smooth during the evolutions, incompatible with predictions of the initially proposed interchange model. In addition, we demonstrate dynamic effects of IR incompatible with the quasi-steady models. Therefore, we prove the necessity of a coronal description which includes fully-dynamic 3D magnetohydrodynamic effects. For sufficiently complex magnetic field structures and evolutions, the predicted dynamics of the quasi-steady and interchange models converge at the coronal hole boundaries. In the end, we offer the consequences of IR on the global coronal magnetic field as a generation mechanism for the slow solar wind.
机译：为了了解日冕的演变和太阳风的产生，有必要了解日冕磁场的结构和动力学。基于现象学的“准稳定”模型是在电晕作为由光球正态通量分布确定的无力平衡状态的时间序列演变的假设下开发的。这些模型成功地预测了整个磁场的极性，整体磁结构和日球电流片的位置。但是，准稳态模型不能解释太阳风的双峰流动结构，也不能解释对磁场动力学有影响的几个日球观测。由于这些局限性，一些研究人员为电晕的发展提出了一种根本不同的范例，即所谓的互换模型。该模型基于互换重新连接（IR）过程，预测了与准稳态视图大不相同的日冕磁场结构。严格来说，IR描述了三维（3D）零点重新连接，其中闭合的双极通量与通向日球的冠状孔通量重新连接。更一般而言，3D零点重新连接机制是嵌套的多极场结构的直接结果，该结构在整个电晕中无处不在。本文旨在对3D零点重新连接机制及其对冠状环境的影响进行严格研究。为此，我们提出了一些相关的模拟，以检查当前的薄板形成和稳定性，以及这种重新连接对整体磁场的结构和动力学的影响。我们显示场拓扑在演化过程中保持平滑，这与最初提出的互换模型的预测不符。此外，我们演示了与拟稳态模型不兼容的IR的动态影响。因此，我们证明了包括全动态3D磁流体动力效应的日冕描述的必要性。对于足够复杂的磁场结构和演化，准稳态和互换模型的预测动力学在冠孔边界处收敛。最后，我们提供了IR对全球日冕磁场的影响，作为太阳缓慢风的一种生成机制。

著录项

  • 作者

    Edmondson, Justin K.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Physics Astrophysics.;Physics Fluid and Plasma.;Physics Electricity and Magnetism.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 190 p.
  • 总页数 190
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

  • 入库时间 2022-08-17 11:37:44

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