arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1701.09082astro-ph.SR
收藏

通量吸积与日冕物质抛射动力学

Flux Accretion and Coronal Mass Ejection Dynamics

Brian T. Welsch

摘要:

日冕物质抛射(CME)是日光层严重空间天气扰动的主要驱动力。已经提出的日冕物质抛射动力学模型没有完全包括磁重联对驱动抛射力的影响。然而,观测和数值模拟都表明,重联可能在大多数(如果不是全部的话)快速日冕物质抛射中起着重要作用。在这里,我们从理论上研究了磁通量的吸积到一个上升的喷射通过重联涉及喷射的背景场。这种重连改变了抛射的磁结构及其环境,从而改变了作用在抛射上的力,通常增加了其向上的加速度。反过来,修改后的力可以更强烈地驱动重连。这种反馈过程实际上是一种不稳定性,我们称之为重连不稳定性。我们的分析意味着,CME模型,忽略重联的影响,不能准确地描述所观察到的CME动态。我们的最终目的是了解CME加速的变化方面的可观察的性质的磁重联,如数量的重联通量。这个通量可以通过观测耀斑带和光球磁场来估算。

英文摘要:

Coronal mass ejections (CMEs) are the primary drivers of severe space weather disturbances in the heliosphere. Models of CME dynamics have been proposed that do not fully include the effects of magnetic reconnection on the forces driving the ejection. Both observations and numerical modeling, however, suggest that reconnection likely plays a major role in most, if not all, fast CMEs. Here, we theoretically investigate the accretion of magnetic flux onto a rising ejection by reconnection involving the ejection's background field. This reconnection alters the magnetic structure of the ejection and its environment, thereby modifying the forces acting upon the ejection, generically increasing its upward acceleration. The modified forces, in turn, can more strongly drive the reconnection. This feedback process acts, effectively, as an instability, which we refer to as a reconnective instability. Our analysis implies that CME models that neglect the effects of reconnection cannot accurately describe observed CME dynamics. Our ultimate aim is to understand changes in CME acceleration in terms of observable properties of magnetic reconnection, such as the amount of reconnected flux. This flux can be estimated from observations of flare ribbons and photospheric magnetic fields.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑