SIMULATIONS OF ALFVÉN AND KINK WAVE DRIVING OF THE SOLAR CHROMOSPHERE: EFFICIENT HEATING AND SPICULE LAUNCHING
SIMULATIONS OF ALFVÉN AND KINK WAVE DRIVING OF THE SOLAR CHROMOSPHERE: EFFICIENT HEATING AND SPICULE LAUNCHING
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DOI：
10.3847/0004-637x/829/2/80
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发表时间：
2016-01
期刊：
影响因子：
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通讯作者：
C. Brady;T. Arber
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文献类型：
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作者：
C. Brady;T. Arber
在我们对太阳色球层的理解中，两个核心问题是：上层色球层是如何被加热的，以及是什么驱动了针状体。根据辐射和导电损耗对所需色球加热的估计表明，在较低的色球层中加热速率为~ 0.1 erg cm−3 s−1，而在较高的色球层中加热速率降至~ 10−3 erg cm−3 s−1。色球层也被针状体渗透，来自低层大气的高密度等离子体以~ 10-20 km s−1的速度向上推进，对于所谓的I型针状体，它们达到光球层以上~ 3000-5000 km的高度。因此，更清楚地了解色球动力学、它的加热和针状体的形成对太阳大气科学至关重要。30多年来，人们提出MHD波的光球驱动可能是加热和针状体形成的原因。本文介绍了高分辨率MHD处理光球驱动的alfv<s:1>和扭结波向上传播到嵌入在模型色球大气中的膨胀通量管中的结果。我们发现，从alfv<s:1>和扭结波到慢模式的重动力耦合产生激波，既加热上层色球层，又驱动针状体。这些模拟表明，太阳色球层的波驱动可以在一个单一的相干模型中给出与观测相匹配的局部加热速率，并驱动与I型观测相一致的针状体。
Two of the central problems in our understanding of the solar chromosphere are how the upper chromosphere is heated and what drives spicules. Estimates of the required chromospheric heating, based on radiative and conductive losses, suggest a rate of ∼0.1 erg cm−3 s−1 in the lower chromosphere and drops to ∼10−3 erg cm−3 s−1 in the upper chromosphere. The chromosphere is also permeated by spicules, higher density plasma from the lower atmosphere propelled upwards at speeds of ∼10–20 km s−1, for so-called Type I spicules, which reach heights of ∼3000–5000 km above the photosphere. A clearer understanding of chromospheric dynamics, its heating, and the formation of spicules is thus of central importance to solar atmospheric science. For over 30 years it has been proposed that photospheric driving of MHD waves may be responsible for both heating and spicule formation. This paper presents results from a high-resolution MHD treatment of photospheric driven Alfvén and kink waves propagating upwards into an expanding flux tube embedded in a model chromospheric atmosphere. We show that the ponderomotive coupling from Alfvén and kink waves into slow modes generates shocks, which both heat the upper chromosphere and drive spicules. These simulations show that wave driving of the solar chromosphere can give a local heating rate that matches observations and drive spicules consistent with Type I observations all within a single coherent model.