First Observation of a Type II Solar Radio Burst Transitioning between a Stationary and Drifting State
First Observation of a Type II Solar Radio Burst Transitioning between a Stationary and Drifting State
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DOI：
10.3847/1538-4357/ab80c1
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
N. Chrysaphi;H. Reid;E. P. Kontar
中科院分区：
文献类型：
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作者：
N. Chrysaphi;H. Reid;E. P. Kontar
静止的II型太阳射电爆发被认为是由静止的II型太阳射电爆发引起的，而漂移的II型爆发则是由通常与日冕物质抛射(CME)有关的运动激波激发的。观测到静止或漂移的II型爆发很常见，但这两种状态之间的转换还没有报道。在这里，我们展示了一次II型爆发，它显示了从静止状态到漂移状态的清晰、连续的转变，这是第一次观察到这类爆发。此外，在爆发的平稳部分观察到了频带分裂，以及在平稳发射中有趣的正负频率漂移精细结构。研究了射电辐射与观测到的急流和窄的CME在多个波长上的关系，并确定了导致II型跃迁爆发的机制。我们发现，喷流喷发产生了流光喷发的CME，CME驱动的激波和流光之间的相互作用很可能是观测到的射电辐射的原因。
Standing shocks are believed to be responsible for stationary Type II solar radio bursts, whereas drifting Type II bursts are excited by moving shocks often related to coronal mass ejections (CMEs). Observations of either stationary or drifting Type II bursts are common, but a transition between the two states has not yet been reported. Here, we present a Type II burst which shows a clear, continuous transition from a stationary to a drifting state, the first observation of its kind. Moreover, band splitting is observed in the stationary parts of the burst, as well as intriguing negative and positive frequency-drift fine structures within the stationary emissions. The relation of the radio emissions to an observed jet and a narrow CME were investigated across multiple wavelengths, and the mechanisms leading to the transitioning Type II burst were determined. We find that a jet eruption generates a streamer-puff CME and that the interplay between the CME-driven shock and the streamer is likely to be responsible for the observed radio emissions.