Subjects: Astronomy submitted time 2023-07-14 Cooperative journals: 《天文学报》
Abstract： Electromagnetic Ion Cyclotron (EMIC) waves in the solar wind have received much attention since they were discovered. EMIC waves are important in the plasma heating and acceleration in the solar wind because they can effectively transfer wave energy to ions via the cyclotron resonance. This paper summarizes the progress of EMIC waves observation and theoretical research in the solar wind, including a series of results obtained from EMIC waves observation in and out of magnetic clouds, Interplanetary Coronal Mass Ejections (ICMEs) sheath region, and the research progress for excitation mechanism of EMIC waves based on observations. Finally, the potential research of EMIC waves in the solar wind in the future is anticipated.
Subjects: Astronomy submitted time 2023-07-14 Cooperative journals: 《天文学报》
Abstract： Kinetic Alfv\'en waves (KAWs) are dispersive Alfv\'en 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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