We examine the relationship between the high-frequency (425 MHz) type?II radio burst and the associated white-light coronal mass ejection (CME) that occurred on 2011 February 13. The radio burst had a drift rate of 2.5 MHz s–1, indicating a relatively high shock speed. From SDO/AIA observations we find that a loop-like erupting front sweeps across high-density coronal loops near the start time of the burst (17:34:17 UT). The deduced distance of shock formation (0.06 Rs) from the flare center and speed of the shock (1100 km s–1) using the measured density from SDO/AIA observations are comparable to the height (0.05 Rs, from the solar surface) and speed (700 km s–1) of the CME leading edge observed by STEREO/EUVI. We conclude that the type?II burst originates even in the low corona (59 Mm or 0.08 Rs, above the solar surface) due to the fast CME shock passing through high-density loops.
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机译：我们研究了2011年2月13日发生的高频（425 MHz）II型无线电爆发与相关的白光日冕物质抛射（CME）之间的关系。无线电爆发的漂移率为2.5 MHz s-1 ，表明较高的冲击速度。从SDO / AIA的观察中，我们发现在爆发开始时间附近（UT下午17:34:17），环状的喷发前掠过高密度冠状环。利用从SDO / AIA观测中测得的密度，推算出距火炬中心的震荡形成距离（0.06 Rs）和震荡速度（1100 km s-1）与高度（距太阳表面0.05 Rs）相当，并且STEREO / EUVI观测到的CME前沿速度（700 km s–1）。我们得出结论，由于快速的CME冲击通过高密度回路，Ⅱ型爆发甚至起源于低电晕（<59 Mm或0.08 Rs，位于太阳表面上方）。
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