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arXiv 1003.0665astro-ph.SR
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太阳耀斑/CME爆发事件中的等离子体团-环顶相互作用和磁流入的证据

Evidence of a Plasmoid-Looptop Interaction and Magnetic Inflows During a Solar Flare/CME Eruptive Event

Ryan O. Milligan, R. T. James McAteer, Brian R. Dennis, C. Alex Young

摘要:

观测证据合并的一个向下传播的等离子体团与looptop内核在2007年1月25日的掩星事件。RHESSI在9-18 keV能量范围内的光变曲线,以及里尔蒙斯太阳天文台245 MHz通道的光变曲线,显示了合并时日冕中增强的非热发射,表明发生了额外的粒子加速。这是由于在两个合并源之间形成的电流片中的二次重连。RHESSI图像用于确定等离子体团的平均向下速度为12公里/秒。STEREO-Behind上的SECCHI仪器套件的补充观测表明,这一过程发生在相关CME的加速阶段。从小波增强的EUVI,图像证据流入磁场线之前的CME喷发也提出。得出的流入速度为1.5 km/s。这种组合的观察支持最近的数值模拟等离子体团的形成,传播和随后的粒子加速由于撕裂模式的不稳定性在电流片形成。

英文摘要:

Observational evidence is presented for the merging of a downward-propagating plasmoid with a looptop kernel during an occulted limb event on 2007 January 25. RHESSI lightcurves in the 9-18 keV energy range, as well as that of the 245 MHz channel of the Learmonth Solar Observatory, show enhanced nonthermal emission in the corona at the time of the merging suggesting that additional particle acceleration took place. This was attributed to a secondary episode of reconnection in the current sheet that formed between the two merging sources. RHESSI images were used to establish a mean downward velocity of the plasmoid of 12 km/s. Complementary observations from the SECCHI suite of instruments onboard STEREO-Behind showed that this process occurred during the acceleration phase of the associated CME. From wavelet-enhanced EUVI, images evidence of inflowing magnetic field lines prior to the CME eruption is also presented. The derived inflow velocity was found to be 1.5 km/s. This combination of observations supports a recent numerical simulation of plasmoid formation, propagation and subsequent particle acceleration due to the tearing mode instability during current sheet formation.

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