在天体物理等离子体中的辐射损失和离子中性碰撞效应
Beatrice Popescu Braileanu1, Rony Keppens1
1Department of Mathematics, Centre for mathematical Plasma Astrophysics, KU Leuven, Celestijnenlaan 200B, Leuven 3001, Belgium.
概括
像太阳冠状状体这样的双流体等离子体中的辐射冷却 (RC) 影响热不稳定性和声波. 包括中性元素在内改变了这些基于电离的效应,再组合显著增加了中性分数.
科学领域:
- 等离子体物理学的物理学
- 天体物理学 天体物理学
- 太阳物理 太阳物理
背景情况:
- 辐射冷却 (RC) 在天体物理等离子体中至关重要,特别是在太阳冠冕中.
- 考虑合中性和带电粒子的双流体模型,比单流体模型提供了更详细的理解.
- 以前对放射性等离子体的研究经常将系统简化为一个流体.
研究的目的:
- 在两流体等离子体模型中研究辐射冷却 (RC) 的作用.
- 分析RC对合中性和带电粒子流体中的热模式和声波的影响.
- 在各种合极限和几何形状中比较分析和数值结果.
主要方法:
- 线性化两流体方程,包括带电粒子能量方程中的辐射损失.
- 用一维几何来分析弱和强合极限的分析处理.
- 在3D和完全非线性2D模拟中对自身值的数值计算.
主要成果:
- 与单流体模型相比,热波和声波的不稳定性条件保持不变.
- RC导致热模式增长和声波缩,与Field (1965) 在弱合极限中一致.
- 中性合将增长/减缓速度降低,其因数取决于电离分数;较高的电离会增加增长速度.
结论:
- 具有RC的双流体模型准确地描述了部分电离等离子体中的热不稳定性和声波缩.
- 电离-再组合动态是显著的,导致冷凝后中性分数大幅增加.
- 这些发现与了解太阳大气中的等离子体过程有关.
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