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arXiv 2103.02661astro-ph.SR
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日冕喷流撞击后的大振幅日珥振荡

Large-amplitude prominence oscillations following the impact by a coronal jet

Manuel Luna, Fernando Moreno-Insertis

摘要:

观测证据表明,日冕喷流可以撞击日冕并使其运动。撞击导致日珥的大振幅振荡(LAO)。在本文中,我们试图通过2.5维MHD数值实验来理解这个过程。在我们的模型中,射流产生在一个剪切的磁弧以上的寄生双极区位于支持日珥的灯丝通道(FC)的足点之一。剪切施加的速度并不远高于观测到的光球值,它会导致一个多重联过程,在以前的喷流模型。一个快速的阿尔夫维尼克扰动和一个较慢的超音速前等离子体射流是从重联网站发出;在后期阶段,一个更激烈的(爆发)射流产生。扰动和喷流沿FC运动,它们部分在日珥反射,部分穿过日珥,导致沿FC的逆流流和日珥振荡。在日珥的部分区域,无论是在纵向还是横向,都有LAO振荡(振幅大于$10~\mathrm{km\, s^{-1}}$)。在某些磁力线中,撞击是如此强烈,以至于日珥质量被带出磁倾角,沿着FC下降到色球层。两种情况下,研究了不同的高度以上的寄生双极区的拱廊,导致不同的高度的区域的突出扰动的射流。得到的振荡幅度和周期与观测结果基本一致。

英文摘要:

Observational evidence shows that coronal jets can hit prominences and set them in motion. The impact leads to large-amplitude oscillations (LAOs) of the prominence. In this paper we attempt to understand this process via 2.5D MHD numerical experiments. In our model, the jets are generated in a sheared magnetic arcade above a parasitic bipolar region located in one of the footpoints of the filament channel (FC) supporting the prominence. The shear is imposed with velocities not far above observed photospheric values; it leads to a multiple reconnection process, as in previous jet models. Both a fast Alfvénic perturbation and a slower supersonic front preceding a plasma jet are issued from the reconnection site; in the later phase, a more violent (eruptive) jet is produced. The perturbation and jets run along the FC; they are partially reflected at the prominence and partially transmitted through it. There results a pattern of counter-streaming flows along the FC and oscillations of the prominence. The oscillations are LAOs (with amplitude above $10~\mathrm{km\, s^{-1}}$) in parts of the prominence both in the longitudinal and transverse directions. In some field lines, the impact is so strong that the prominence mass is brought out of the dip and down to the chromosphere along the FC. Two cases are studied with different heights of the arcade above the parasitic bipolar region, leading to different heights for the region of the prominence perturbed by the jets. The obtained oscillation amplitudes and periods are in general agreement with the observations.

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。

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