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arXiv 1406.2363astro-ph.SRphysics.space-ph
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日冕Shock Wave作为早期SEP加速驱动源的性质

Properties of a Coronal Shock Wave as A Driver of Early SEP Acceleration

Kamen A. Kozarev, John C. Raymond, Vasili V. Lobzin, Michael Hammer

摘要:

日冕物质抛射(CME)被认为是在日冕中驱动无碰撞冲击,而这反过来又被证明能够在几分钟内加速太阳高能粒子(SEP)。众所周知,由于缺乏现场测量,提取日冕中高能粒子光谱的信息非常困难。然而,有可能将远程观测与数据驱动模型相结合,以推断与SEP的局部加速及其日光层与近地空间的连通性相关的日冕冲击特性。我们提出了这种新颖的分析应用于2011年5月11日CME事件的西太阳翼,重点是火山爆发驱动的,圆顶状的冲击波的演变所观察到的大气成像组件(AIA)EUV望远镜在船上的太阳动力学天文台航天器。我们分析了冲击的演变,并估计其强度使用排放措施建模。我们采用一种新的方法相结合的几何模型的冲击波阵面的位场源表面模型,以估计时间依赖的字段冲击角和日光层连接在低电晕冲击通道。我们发现,冲击波很弱,初速度约为450 km/s。它最初大部分是准平行的,但在后来的事件中,它的大部分变成了准垂直的。据AIA仪器观测,在该事件接近尾声时,近地空间的磁连通性良好。在这项分析中使用的方法举行了显着的潜在的早期表征日冕冲击波和预测SEP光谱的基础上远程观测。

英文摘要:

Coronal mass ejections (CMEs) are thought to drive collisionless shocks in the solar corona, which in turn have been shown capable of accelerating solar energetic particles (SEPs) in minutes. It has been notoriously difficult to extract information about energetic particle spectra in the corona, due to lack of in-situ measurements. It is possible, however, to combine remote observations with data-driven models in order to deduce coronal shock properties relevant to the local acceleration of SEPs and their heliospheric connectivity to near-Earth space. We present such novel analysis applied to the May 11, 2011 CME event on the western solar limb, focusing on the evolution of the eruption-driven, dome-like shock wave observed by the Atmospheric Imaging Assembly (AIA) EUV telescopes on board the Solar Dynamics Observatory spacecraft. We analyze the shock evolution and estimate its strength using emission measure modeling. We apply a new method combining a geometric model of the shock front with a potential field source surface model to estimate time-dependent field-to-shock angles and heliospheric connectivity during shock passage in the low corona. We find that the shock was weak, with an initial speed of ~450 km/s. It was initially mostly quasi-parallel, but significant portion of it turned quasi-perpendicular later in the event. There was good magnetic connectivity to near-Earth space towards the end of the event as observed by the AIA instrument. The methods used in this analysis hold a significant potential for early characterization of coronal shock waves and forecasting of SEP spectra based on remote observations.

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