Linear Analysis of Shear-Flow Instabilities in a Prominence-Corona Interface with Ambipolar Diffusion

IF 2.7 3区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Solar Physics Pub Date : 2025-05-22 DOI:10.1007/s11207-025-02481-5

Llorenç Melis, Roberto Soler

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Abstract

Observations have shown the presence of the Kelvin–Helmholtz instability (KHi) in solar prominences. Effects due to partial ionization of the prominence plasma may influence the KHi onset. We study the triggering of the KHi in an interface model that consists of a partially ionized prominence region and a fully ionized coronal region, with a uniform magnetic field parallel to the interface. There is a longitudinal flow in the prominence region. The plasma is compressible and the role of ambipolar diffusion, which accounts for collisions between charges and neutrals, is taken into account in the prominence plasma. We derive the dispersion relation of linear perturbations on the interface and analyze some limit cases analytically. Numerical results are obtained for realistic prominence parameters. We find that compressibility and gas pressure are important in determining the unstable flow velocities, specially in the range of sub-Alfvénic flows that are consistent with the observations. The ambipolar diffusion has a generally destabilizing influence and reduces the threshold flow velocity for the KHi onset.

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双极性扩散的日珥-日冕界面剪切流动不稳定性的线性分析

观测表明在日珥中存在开尔文-亥姆霍兹不稳定性（KHi）。由于日珥等离子体部分电离的影响可能影响KHi的发病。我们在一个由部分电离的日珥区和完全电离的日冕区组成的界面模型中研究了KHi的触发，该模型具有平行于界面的均匀磁场。在日珥区域存在纵向流动。等离子体是可压缩的，并且在日珥等离子体中考虑了双极性扩散的作用，这解释了电荷和中性粒子之间的碰撞。导出了界面上线性扰动的色散关系，并解析分析了一些极限情况。对实际的日珥参数进行了数值计算。我们发现可压缩性和气体压力在确定不稳定流动速度方面是重要的，特别是在与观测结果一致的亚阿尔夫萨奇流动范围内。双极扩散具有普遍的不稳定影响，并降低了KHi开始的阈值流速。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Solar Physics 地学天文-天文与天体物理

CiteScore

5.10

自引率

17.90%

发文量

146

审稿时长

1 months

期刊介绍： Solar Physics was founded in 1967 and is the principal journal for the publication of the results of fundamental research on the Sun. The journal treats all aspects of solar physics, ranging from the internal structure of the Sun and its evolution to the outer corona and solar wind in interplanetary space. Papers on solar-terrestrial physics and on stellar research are also published when their results have a direct bearing on our understanding of the Sun.