CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH
CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH
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磁通量鞘中色球和日冕波的产生
DOI：
10.3847/0004-637x/827/1/7
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Carlsson
中科院分区：
文献类型：
--
作者：
Y. Kato;O. Steiner;V. Hansteen;B. Gudiksen;S. Wedemeyer;M. Carlsson
利用辐射磁流体动力学模拟的太阳大气层从对流层的上部到较低的日冕，我们调查的自洽激发慢磁声体波（慢模式）的磁通量集中。我们发现，在附近的二维通量板的对流下降气流“泵”的等离子体在向下的方向。这一作用在通量板内部产生向下流动，通量板包含更高的层，导致向上传播的稀疏波。慢模由光学表面附近的下降流的绝热压缩激发，以管速度沿向上的方向沿着磁场传播。它在色球层高度发展成冲击波，在那里消散，抬升过渡区，并以压缩波的形式产生后代，进一步传播到日冕中。在下降气流和传播激波的尾流中，色球层和更高层的通量板内的大气倾向于以ν/4 mHz的周期振荡。我们的结论是，这个过程中的“磁泵”是一个最合理的机制，直接产生的纵向色球和日冕压缩波内的磁通量浓度，它可能会提供一个重要的热源在色球。它也可能负责某些类型的动态原纤维。
Using radiation magnetohydrodynamic simulations of the solar atmospheric layers from the upper convection zone to the lower corona, we investigate the self-consistent excitation of slow magneto-acoustic body waves (slow modes) in a magnetic flux concentration. We find that the convective downdrafts in the close surroundings of a two-dimensional flux slab “pump” the plasma inside it in the downward direction. This action produces a downflow inside the flux slab, which encompasses ever higher layers, causing an upwardly propagating rarefaction wave. The slow mode, excited by the adiabatic compression of the downflow near the optical surface, travels along the magnetic field in the upward direction at the tube speed. It develops into a shock wave at chromospheric heights, where it dissipates, lifts the transition region, and produces an offspring in the form of a compressive wave that propagates further into the corona. In the wake of downflows and propagating shock waves, the atmosphere inside the flux slab in the chromosphere and higher tends to oscillate with a period of ν ≈ 4 mHz. We conclude that this process of “magnetic pumping” is a most plausible mechanism for the direct generation of longitudinal chromospheric and coronal compressive waves within magnetic flux concentrations, and it may provide an important heat source in the chromosphere. It may also be responsible for certain types of dynamic fibrils.
太阳大气中传播的 MHD 扭结波的产生和阻尼
DOI：
10.1088/0004-637x/784/1/29
发表时间：
2014
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Morton R
通讯作者：
Morton R
影响因子：
1.9
作者：
Fedun, V.;Shelyag, S.;Erdelyi, R.
通讯作者：
Erdelyi, R.