标题： 2011年2月9日的分米型U型太阳射电爆发及其相关的EUV现象 显示英文标题

标题： Decimetric type U solar radio bursts and associated EUV phenomena on 2011 February 9

摘要： 2011年2月9日，在活动区AR 11153发生了一次GOES M1.9级耀斑。使用200 kHz的分辨率和80毫秒的时间采样率，云南天文台太阳射电频谱仪（YNSRS）观测到了反漂移（RS）III型爆发现象、间歇性U型爆发序列、漂移脉动结构（DPS）以及精细结构。多波段数据联合信息显示，在YNSRS观测到的DPS之后，U型爆发的发生率突然增加了5倍。在此事件中，U型爆发的发生率可能依赖于磁重联速率。我们的观测结果与先前的数值模拟结果一致。在第一次等离子体团产生（等离子体不稳定性发生）后，磁重联速率突然增加了5至8倍。此外，在DPS之后，U型爆发的转折频率范围明显拓宽了3倍，这表明环顶密度的波动幅度增大。我们的观测也支持耀斑冲动相期间的数值模拟结果。湍流发生在耀斑环顶部，等离子体团可以捕获非热粒子，并在环顶引起密度波动。这些观测结果总体上与数值模拟的结果一致，有助于我们更好地理解爆发全过程的物理特性。 显示英文摘要

摘要： A GOES M1.9 flare took place in active region AR 11153 on February 9,2011. With the resolution of 200 kHz and a time cadence of 80 ms, the reverse-drifting (RS) type III bursts, intermittent sequence of type U bursts, drifting pulsation structure (DPS), and fine structures were observed by the Yunnan Observatories Solar Radio Spectrometer(YNSRS). Combined information revealed by the multi-wavelength data indicated that after the DPS which observed by YNSRS, the generation rate of type U bursts suddenly increased 5 times than before. In this event, the generation rate of type U bursts may depend on the magnetic reconnection rate. Our observations are consistent with previous numerical simulations results. After the first plasmoid produced (plasma instability occurred), the magnetic reconnection rate increased suddenly 5-8 times than before. Furthermore, after the DPS, the frequency range of turnover frequency of type U bursts is obviously broadened 3 times than before, which indicates the fluctuation amplitude of the density in the loop-top. Our observations also support the numerical simulations during the flare impulsive phase. The turbulence occurs at the top of the flare loop, the plasmoids can trap the non-thermal particles and cause the density fluctuation at the loop-top. The observations are generally consistent with the results of numerical simulations, helping us to better understand the characteristics of the whole physical process of eruption.