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arXiv · 1810.11815

Source Imaging of a Moving Type-IV Solar Radio Burst and its Role in Tracking Coronal Mass Ejection From the Inner to the Outer Corona

V. Vasanth·Yao Chen·Maoshui Lv·Hao Ning·Chuangyang Li·Shiwei Feng·Zhao Wu·Guohui Du
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Abstract

Source imaging of solar radio bursts can be used to track energetic electrons and associated magnetic structures. Here we present a combined analysis of data at different wavelengths for an eruption associated with a moving type-IV (t-IVm) radio burst. In the inner corona, the sources are correlated with a hot and twisted eruptive EUV structure, while in the outer corona the sources are associated with the top front of the bright core of a white light coronal mass ejection (CME). This reveals the potential of using t-IVm imaging data to continuously track the CME by lighting up the specific component containing radio-emitting electrons. It is found that the t-IVm burst presents a clear spatial dispersion with observing frequencies. The burst manifests broken power-law like spectra in brightness temperature, which is as high as $10^7$-$10^9$ K while the polarization level is in-general weak. In addition, the t-IVm burst starts during the declining phase of the flare with a duration as long as 2.5 hours. From the differential emission measure analysis of AIA data, the density of the T-IVm source is likely at the level of 10$^8$ cm$^{-3}$ at the start of the burst, and the temperature may reach up to several MK. These observations do not favor gyro-synchrotron to be the radiation mechanism, yet in line with a coherent plasma emission excited by energetic electrons trapped within the source. Further studies are demanded to elucidate the emission mechanism and explore the full diagnostic potential of t-IVm bursts.

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V. Vasanth, Yao Chen, Maoshui Lv, Hao Ning, Chuangyang Li, Shiwei Feng, Zhao Wu, Guohui Du. 2018-10-28. Source Imaging of a Moving Type-IV Solar Radio Burst and its Role in Tracking Coronal Mass Ejection From the Inner to the Outer Corona. https://doi.org/10.3847/1538-4357%2Faaeffd

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