日冕磁场和重联的射电信号  

Radio Signature of Coronal Magnetic Field and Reconnection

作　　者：黄光力[1] 

机构地区：[1]中国科学院紫金山天文台,江苏南京210008

出　　处：《天文研究与技术》2006年第2期99-112,共14页Astronomical Research & Technology

基　　金：国家自然科学基金(10333030;10273025);"973"项目(G2000078403)资助

摘　　要：总结了近期用射电频谱仪(高时间和高频谱分辨)和野边山射电日像仪(高空间分辨)以及国内外其它空间和地面设备分析日冕磁场和重联的系列工作。主要结论可归纳为:1)在Dulk等人(1982)的近似下自恰计算射电爆发源区磁场的平行和垂直分量,并首次得到该磁场在日面的两维分布。2)为了考虑非热电子低能截止的影响,必须采用更严格的回旋同步辐射理论来计算。结果表明:低能截止和日冕磁场对计算有明显的影响,而其它参数(包括背景温度、密度、高能截止和辐射方向)的影响均可忽略。因此,对低能截止和日冕磁场必须联立求解。3)射电爆发中的精细结构可能反映了射电爆发源比较靠近粒子加速(磁场重联)的区域,利用高时间和高频率分辨的频谱仪和高空间分辨的日像仪联合分析,可以确定精细结构的源区位置,从而确定粒子加速(磁场重联)的准确时间和地点。A series of recent works using the radio spectrometer （with high time and frequency resolutions） and Nobeyama Radio Heliograph （with high spatial resolution） for analysis coronal magnetic field and reconnection are summarized in this paper. The main conclusions include： 1 ） Under the approximations of Dulk et al （1982）, the parallel and perpendicular components of the magnetic field in the sources of radio bursts are calculated self - consistently, and 2-dimensional distribution was obtained firstly. 2） To consider the effect of low-cutoff energy of non-thermal electrons, it is necessary to calculate with more strict theory of gyro-synchrotron radiation. It is shown that the low-cutoff energy has evident effect on the calculations, but the effects of the other parameters （such as the ambient temperature and density, high-cutoff energy, and emission direction） may be neglected. Therfore the low-cutoff energy and coronal magnetic field should be solved together. 3） The fine structures in radio bursts may show that the sources of the radio bursts are located close to the particle acceleration （magnetic reconnection） sites. It is possible to fix the locations of the sources of the fine structures, as well as the exact location and time of the particle acceleration （magnetic reconnection） using the radio spectrometer with high time and frequency resolutions and radio heliograph with high spatial resolution. These works are concentrated in the recent key points of solar physics, and will be developed further.

关 键 词：日冕磁场 重联 射电爆发 精细结构 

分 类 号：P182.62[天文地球—天文学]