SHINE: Comparison and Assessment of the Flux Cancellation and Breakout Models for Coronal Mass Ejection (CME) Initiation

SIRE计划和整个太阳物理学的一个关键目标是了解日冕物质抛射(CME)的起源。这些巨大的喷发将等离子体和磁通量推离太阳，并被认为是主要地磁风暴的主要原因。在最近的SISH研讨会上，“通量抵消”和“爆发”这两种机制作为日冕物质抛射的可能触发机制受到了广泛关注。讲习班进行了热烈的讨论，对具体活动的这些机制进行了赞成或反对的辩论，但没有就这两种机制的合理性达成共识。主要的困难是，大多数已经提出的作为通量抵消或爆发的例子的模拟过于理想化，无法解决在特定事件中观察到的关键特征。在这项提议中，提出者描述了一个为期三年的计划，以研究CMES的通量抵消和爆发模型。总体目标是确定这两个模型中的任何一个是否能够为类似真实事件的参数产生喷发。具体地说，PI和他的团队将：*为两个研究得很好的事件：1997年5月12日的CME事件和2000年7月14日的“巴士底日”事件建立日冕的MHD模型；*调查包括太阳风的配置的磁场拓扑，特别是分离线表面位置的变化(这对爆发模型至关重要)；*用SOHO MDI仪器研究导致事件的通量变化是否足以产生喷发；*诊断通过分离线表面(爆发)与光球处的重新连接(通量抵消)的竞争效应在产生喷发中的作用；以及*评估每种机制作为这些事件的触发因素的可行性。

A key goal of the SHINE program and of solar physics in general is to understand the initiation of coronal mass ejections (CMEs). These immense eruptions propel plasma and magnetic flux outward from the sun, and are believed to be the primary cause of major geomagnetic storms. At recent SHINE workshops, two mechanisms, "flux cancellation" and "breakout," have received prominent attention as the possible trigger for CMEs. The workshops have featured lively discussions arguing either in favor of or against these mechanisms for specific events, but no consensus has been reached concerning the plausibility of either mechanism. The central difficulty is that most of the simulations that have been put forth as examples of flux cancellation or breakout have been too idealized to address the key features observed in the specific events.In this proposal, the proposers describe a three-year program to investigate the flux cancellation and breakout models of CMEs. The overall goal is to determine whether either of these models can produce eruptions for parameters similar to real events. Specifically, the PI and his team will: * Develop MHD models of the corona for the time of two well studied events: the May 12, 1997 CME event and the July 14, 2000 "Bastille Day" event;* Investigate the magnetic field topology of the configurations when solar wind is included, especially changes to the location of separatrix surfaces (which are crucial for the breakout model);* Study whether flux changes leading up to the event with the SOHO MDI instrument are sufficient to produce eruptions;* Diagnose the role of the competing effects of reconnection through separatrix surfaces (breakout) versus reconnection at the photosphere (flux cancellation) in producing eruptions; and* Assess each mechanism's feasibility as the trigger for these events.