Global Forces in Eruptive Solar Flares: The Lorentz Force Acting on the Solar Atmosphere and the Solar Interior
Global Forces in Eruptive Solar Flares: The Lorentz Force Acting on the Solar Atmosphere and the Solar Interior
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DOI：
10.1007/s11207-011-9907-2
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发表时间：
2012-03-01
期刊：
影响因子：
2.8
通讯作者：
Hudson, H. S.
中科院分区：
文献类型：
--
作者：
Fisher, G. H.;Bercik, D. J.;Hudson, H. S.
我们计算了在大规模爆发性太阳耀斑期间观测到的矢量磁图变化所隐含的、在太阳外层大气上积分的洛伦兹力的变化。这种力的扰动应该由作用在太阳光球层和太阳内部的一个大小相等、方向相反的力的扰动来平衡。由此得到的太阳内部估计力变化的表达式推广了哈德森、费舍尔和韦尔施（《太平洋天文学会会议系列 - 383》，221页，2008年）提出的早期表达式，提供了水平和垂直力分量，并为扰动力的垂直分量提供了更准确的结果。我们表明，磁爆发应该导致光球层的磁场变得更加水平，因此应该导致一个向下（朝向太阳内部）的力的变化作用在光球层和太阳内部，正如王和刘（《天体物理学杂志通讯》716卷，L195页，2010年）最近从对磁图数据的分析中所论证的那样。我们提出，从矢量磁图变化计算出的力的变化、耀斑抛射物所携带的向外动量以及由向下力的变化驱动的日震扰动的特性之间存在一种观测关系。我们利用太阳外层大气中洛伦兹力变化所驱动的冲量来推导能够从太阳逃逸的喷发等离子体质量的上限。最后，我们将光球层预期的洛伦兹力变化与由耀斑驱动的气体动力学扰动的简单估计以及在耀斑条件下光球层辐射反照加热引起的扰动压力的估计进行了比较。
We compute the change in the Lorentz force integrated over the outer solar atmosphere implied by observed changes in vector magnetograms that occur during large, eruptive solar flares. This force perturbation should be balanced by an equal and opposite force perturbation acting on the solar photosphere and solar interior. The resulting expression for the estimated force change in the solar interior generalizes the earlier expression presented by Hudson, Fisher, and Welsch (Astron. Soc. Pac. CS-383, 221, 2008), providing horizontal as well as vertical force components, and provides a more accurate result for the vertical component of the perturbed force. We show that magnetic eruptions should result in the magnetic field at the photosphere becoming more horizontal, and hence should result in a downward (toward the solar interior) force change acting on the photosphere and solar interior, as recently argued from an analysis of magnetogram data by Wang and Liu (Astrophys. J. Lett. 716, L195, 2010). We suggest the existence of an observational relationship between the force change computed from changes in the vector magnetograms, the outward momentum carried by the ejecta from the flare, and the properties of the helioseismic disturbance driven by the downward force change. We use the impulse driven by the Lorentz-force change in the outer solar atmosphere to derive an upper limit to the mass of erupting plasma that can escape from the Sun. Finally, we compare the expected Lorentz-force change at the photosphere with simple estimates from flare-driven gasdynamic disturbances and from an estimate of the perturbed pressure from radiative backwarming of the photosphere in flaring conditions.