Lost and found sunquake in the 6 September 2011 flare caused by beam electrons
Lost and found sunquake in the 6 September 2011 flare caused by beam electrons
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DOI：
10.1051/0004-6361/201832896
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发表时间：
2018-11
影响因子：
6.5
通讯作者：
Connor Macrae;S. Zharkov;V. Zharkova;M. Druett;S. Matthews;T. Kawate
中科院分区：
文献类型：
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作者：
Connor Macrae;S. Zharkov;V. Zharkova;M. Druett;S. Matthews;T. Kawate
NOAA 11283 活动区于 2011 年 9 月 6 日至 7 日产生了两次 X 级耀斑，许多作者对此进行了深入研究。 X2.1级耀斑发生于2011年9月6日，与该地区产生的两个同源白光耀斑中的第一个相关，但尽管在2011年9月7日的第二个耀斑中检测到了日震，但没有发现日震。在本文中，我们提出了对2011年9月6日耀斑的首次日震观测，该观测是通过对出射功率的统计显着性分析检测到的，并通过定向全息图和时间距离图进行了验证。表面波前表现出西北方向的方向偏好我们结合电子束加热的耀斑大气的辐射流体动力学模型和超音速冲击在太阳内部产生声波的流体动力学模型来解释这次日震和相关的耀斑发射。耀斑大气的流体动力学模型会产生以超音速向光球层及其下方传播的流体动力学冲击。我们首次得出了内部给定深度处激波沉积的速度（高达 140 km s−1）和爆发时间（耀斑爆发后约 50 秒）。冲击波参数由从该耀斑观察到的硬 X 射线和白光发射的辐射特征证实。研究发现，耀斑下方内部的激波传播会产生沿激波传播方向拉长的声波，从而导致在太阳表面看到各向异性波前。将太阳表面检测到的地震特征与模拟激波速度导出的声波前模型相匹配，我们推断激波必须以与当地太阳垂直线成约 30° 的角度沉积。因此，改进的地震探测技术与本研究报告的双流体动力学模型相结合，为观测和解释太阳耀斑地震特征开辟了新的视角。
The active region NOAA 11283 produced two X-class flares on 6 and 7 September 2011 that have been well studied by many authors. The X2.1 class flare occurred on September 6, 2011 and was associated with the first of two homologous white light flares produced by this region, but no sunquake was found with it despite the one being detected in the second flare of 7 September 2011. In this paper we present the first observation of a sunquake for the 6 September 2011 flare detected via statistical significance analysis of egression power and verified via directional holography and time–distance diagram. The surface wavefront exhibits directional preference in the north-west direction We interpret this sunquake and the associated flare emission with a combination of a radiative hydrodynamic model of a flaring atmosphere heated by electron beam and a hydrodynamic model of acoustic wave generation in the solar interior generated by a supersonic shock. The hydrodynamic model of the flaring atmosphere produces a hydrodynamic shock travelling with supersonic velocities toward the photosphere and beneath. For the first time we derive velocities (up to 140 km s−1) and onset time (about 50 s after flare onset) of the shock deposition at given depths of the interior. The shock parameters are confirmed by the radiative signatures in hard X-rays and white light emission observed from this flare. The shock propagation in the interior beneath the flare is found to generate acoustic waves elongated in the direction of shock propagation, that results in an anisotropic wavefront seen on the solar surface. Matching the detected seismic signatures on the solar surface with the acoustic wave front model derived for the simulated shock velocities, we infer that the shock has to be deposited under an angle of about 30° to the local solar vertical. Hence, the improved seismic detection technique combined with the double hydrodynamic model reported in this study opens new perspectives for observation and interpretation of seismic signatures in solar flares.