1. 丽水学院工学院 丽水 323000;2. 中国科学院紫金山天文台行星科学重点实验室 南京 210023;3. 洛阳师范学院空间物理研究所 洛阳 471934
1. College of Engineering and Design, Lishui University, Lishui 323000;2. Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023;3. Institute of Space Physics, Luoyang Normal University, Luoyang 471934;
太阳射电爆发(Solar Radio Burst, SRB)是太阳高能电子与背景等离子体相互作用产生的感应辐射现象, 其多样的动力学谱类型及其复杂的精细结构反映了辐射源区磁等离子体结构状态丰富的物理信息, 而相关 辐射机制则是解读相关物理信息的关键工具. 长期以来, 在SRB辐射机制的研究中一直存在着争议不决的 两种主要机制, 即等离子体辐射机制和电子回旋脉泽(Electron Cyclotron Maser, ECM)辐射机制. 近年来, 针对传统的ECM辐射机制 应用到SRB现象时遇到的一些主要困难, 发展了由幂律谱电子低能截止驱动和包含快电子束自生阿尔文 波效应的新型ECM驱动模型, 并成功应用于解释各类不同SRB动力学谱的形成 机制. 基于这些新型的ECM辐射模型, 系统地总结了ECM辐射机制在各种不同类型SRB现象中的应用, 并对它们不同动力学谱结构的形成给出了一致统一的物理解释.
Radio bursts are ubiquitous in the cosmic plasma. Solar radio emission mainly comes from the outer atmosphere of the sun. It is an induced radiation phenomenon generated by the interaction between energetic electrons and solar atmospheric plasma. Different dynamic spectra of solar radio bursts (SRBs) contain physical information of the plasma structure and state in the radiation source region. Therefore, the radiative mechanism of radio bursts has always been the object of research. There are two kinds of coherent radiation mechanisms related to solar radio bursts: one is the plasma radiation mechanism based on electron Langmuir frequency; the other is the electron cyclotron maser (ECM) radiation mechanism based on the electron cyclotron frequency. Although these two radiation mechanisms were proposed almost at the same time, based on the understanding of the coronal environment and the ECM mechanism at that time, the ECM radiation mechanism did encounter some difficulties in explaining SRBs. Until 1979, Wu & Lee introduced the relativistic effect and used the ECM radiation to explain the earth's Auroral Kilometric Radiation (AKR). Since then, the ECM emission has attracted wide attention. Considering some difficulties in applying the ECM emission mechanism to SRBs, we proposed a series of modified models in recent years. Firstly, the cutoff in the energy spectrum of the power-law electrons can effectively drive the ECM instability without relying on the anisotropic distribution of electron velocity. Secondly, considering the influence of Alfvén wave perturbations which are prevalent in space and celestial plasmas, a self-consistent ECM emission mechanism excited by energetic electron beams is developed. On this basis, this paper summarizes the application of the ECM emission mechanism in traditional SRB phenomena from type I to V and microwave SRBs in recent years.
唐建飞,吴德金,赵国清,陈玲.太阳射电爆发现象中的电子回旋脉泽辐射[J].天文学报,2023,(3):32. TANG Jian-fei, WU De-jin, ZHAO Guo-qing, CHEN Ling. Electron Cyclotron Maser Emission in Solar Radio Bursts[J]. Acta Astronomica Sinica,2023,(3):32.复制