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太阳大气中动力学阿尔文波的产生与加热研究进展

Research Progress on the Generation and Heating of Kinetic Alfvén Waves in the Solar Atmosphere

  • 摘要: 动力学阿尔文波是垂直波长接近离子回旋半径或者电子惯性长度的色散阿尔文波. 由于波的尺度接近粒子的动力学尺度, 动力学阿尔文波在太阳和空间等离子体加热、加速等能化现象中起重要作用. 因此, 动力学阿尔文波通常被认为是日冕加热的候选者. 本研究工作深入、系统地调研了太阳大气中动力学阿尔文波的激发和耗散机制. 基于日冕等离子体环境, 介绍了几种常见的动力学阿尔文波激发机制: 温度各向异性不稳定性、场向电流不稳定性、电子束流不稳定性、密度非均匀不稳定性以及共振模式转换. 还介绍了太阳大气中动力学阿尔文波的耗散机制, 并讨论了这些耗散机制对黑子加热、冕环加热以及冕羽加热的影响. 不仅为认识太阳大气中动力学阿尔文波的驱动机制、动力学演化特征以及波粒相互作用提供合理的理论依据, 而且有助于揭示日冕等离子体中能量储存和释放、粒子加热等能化现象的微观物理机制.

     

    Abstract: Kinetic Alfvén waves (KAWs) are dispersive Alfvén waves with a perpendicular wavelength comparable to the ion gyroradius or the electron inertial length. Due to the scale of waves matching to the kinetic scale of particles, KAWs can play an important role in the heating and acceleration of particles in solar and space plasmas. Therefore, KAWs are often regarded as a candidate for the coronal heating. In this paper, the excitation and dissipation mechanisms of KAWs in the solar atmosphere are investigated systematically. Based on the coronal plasma environment, this paper introduces several excitation mechanisms of KAWs: anisotropic temperature instability, field-aligned current instability, electron beam instability, density inhomogeneity instability and resonant mode conversion. The dissipation mechanisms of KAWs in the solar atmosphere are introduced, and their effects on the plasma heating in the sunspot, coronal loop and coronal plume are also discussed. This review not only provides a reasonable theoretical basis for understanding the driving mechanism, dynamic evolution characteristics and wave-particle interaction of KAWs in the solar atmosphere, but also helps to reveal the microscopic physical mechanism of energy storage and release, as well as particle heating in the corona.

     

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