论文标题

太阳微叶片中电子加速的短寿命发作的无线电和X射线观察

Radio and X-ray Observations of Short-lived Episodes of Electron Acceleration in a Solar Microflare

论文作者

Sharma, Rohit, Battaglia, Marina, Luo, Yingjie, Chen, Bin, Yu, Sijie

论文摘要

太阳耀斑是由磁重新连接引起的太阳电晕中突然的能量释放事件,可加速颗粒并加热环境等离子体。在耀斑期间,通常会有多个,时间和空间分离的单个能量释放发作,这些发作可能很难根据观察仪器解决。 We present multi-wavelength imaging and spectroscopy observations of multiple electron acceleration episodes during a GOES B1.7-class two-ribbon flare on 2012 February 25, observed simultaneously with the Karl G. Jansky Very Large Array (VLA) at 1--2 GHz, the Reuven Ramatay High Energy Solar Spectroscopic Imager (RHESSI) in X-rays, and the Solar Dynamics Observatory在极端紫外线(EUV)中。在耀斑的初始阶段,观察到五个无线电爆发。在前三个无线电爆发中,可以看到非热X射线源的同时X射线源,但没有共同空间。它们的无线电光谱被解释为光学厚的陀螺仪发射。通过将无线电光谱与陀螺仪模型拟合,我们在每个加速度发作中得出了磁场强度和非热电子光谱参数。值得注意的是,从X射线中得出的非热参数与从无线电推论的非热参数有很大差异。这些观察结果表明在太阳微叶片的冲动阶段,多个,同时的加速度发作。 X射线和无线电爆发源可能起源于不同磁性回路中的单独电子分布。

Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated individual energy release episodes that can be difficult to resolve depending on the observing instrument. We present multi-wavelength imaging and spectroscopy observations of multiple electron acceleration episodes during a GOES B1.7-class two-ribbon flare on 2012 February 25, observed simultaneously with the Karl G. Jansky Very Large Array (VLA) at 1--2 GHz, the Reuven Ramatay High Energy Solar Spectroscopic Imager (RHESSI) in X-rays, and the Solar Dynamics Observatory in extreme ultraviolet (EUV). During the initial phase of the flare, five radio bursts were observed. A nonthermal X-ray source was seen co-temporal, but not co-spatial, with the first three radio bursts. Their radio spectra are interpreted as optically thick gyrosynchrotron emission. By fitting the radio spectra with a gyrosynchrotron model, we derive the magnetic field strength and nonthermal electron spectral parameters in each acceleration episode. Notably, the nonthermal parameters derived from X-rays differ considerably from the nonthermal parameters inferred from the radio. The observations are indicative of multiple, co-temporal acceleration episodes during the impulsive phase of a solar microflare. The X-ray and radio burst sources likely originate from separate electron distributions in different magnetic loops.

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