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arXiv 0710.0185astro-ph
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动态冠状环的高效建模

Highly Efficient Modeling of Dynamic Coronal Loops

J. A. Klimchuk, S. Patsourakos, P. J. Cargill

备注：
34 pages, 8 figures, accepted by Astrophysical Journal (minor revisions of original submitted version)
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摘要：

观测和理论证据表明，日冕加热是脉冲式的，发生在非常小的跨场空间尺度上。一个单一的日冕环可以包含一百个或更多的单独的链，这些链被纳米火花准独立地加热。因此，对整个活动区域或全球日冕进行建模是一项艰巨的任务。三维MHD代码的空间分辨率不足，一维Hydro代码太慢，无法模拟必须以合理表示方式处理的数千个元素链。幸运的是，热传导和流动倾向于平滑沿磁场的等离子体梯度，所以“0 D模型”是一个可接受的替代方案。我们开发了一个高效的模型，称为基于焓的热循环演化（EBTEL），它准确地描述了沿日冕链的平均温度，压力和密度的演化。它在准确性、灵活性和能力方面大大改进了这种类型的早期模型。它处理缓慢变化和高脉冲日冕加热;它提供了差分发射测量分布，DEM（T），在过渡区的脚点;并有热通量饱和和非热电子束加热的选项。EBTEL提供了良好的协议，更复杂的一维水力模拟，尽管使用四个数量级的计算时间少。它有望成为太阳和恒星研究的强大新工具。

英文摘要：

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated quasi-independently by nanoflares. It is therefore an enormous undertaking to model an entire active region or the global corona. Three-dimensional MHD codes have inadequate spatial resolution, and 1D hydro codes are too slow to simulate the many thousands of elemental strands that must be treated in a reasonable representation. Fortunately, thermal conduction and flows tend to smooth out plasma gradients along the magnetic field, so "0D models" are an acceptable alternative. We have developed a highly efficient model called Enthalpy-Based Thermal Evolution of Loops (EBTEL) that accurately describes the evolution of the average temperature, pressure, and density along a coronal strand. It improves significantly upon earlier models of this type--in accuracy, flexibility, and capability. It treats both slowly varying and highly impulsive coronal heating; it provides the differential emission measure distribution, DEM(T), at the transition region footpoints; and there are options for heat flux saturation and nonthermal electron beam heating. EBTEL gives excellent agreement with far more sophisticated 1D hydro simulations despite using four orders of magnitude less computing time. It promises to be a powerful new tool for solar and stellar studies.

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。

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