Coronal Magnetic Field Measurements along a Partially Erupting Filament in a Solar Flare
Coronal Magnetic Field Measurements along a Partially Erupting Filament in a Solar Flare
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DOI：
10.3847/1538-4357/ac2f99
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发表时间：
2021-10
期刊：
影响因子：
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通讯作者：
Yuqian Wei;B. Chen 陈;Sijie 思捷 Yu 余;Haimin Wang;J. Jing;D. Gary
中科院分区：
文献类型：
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作者：
Yuqian Wei;B. Chen 陈;Sijie 思捷 Yu 余;Haimin Wang;J. Jing;D. Gary
磁通绳是太阳爆发的核心。对磁通绳磁场的直接测量对于理解触发和能量释放过程至关重要，但迄今为止仍然难以捉摸。在这里，我们报告了2017年9月6日发生的m1.4级太阳耀斑的微波成像光谱观测，使用了扩展欧文斯谷太阳能阵列获得的数据。这次耀斑事件与大熊太阳天文台的古德太阳望远镜在Hα观测到的扭曲细丝的部分喷发有关。该事件的极紫外（EUV）和x射线特征通常与爆发耀斑的标准场景一致，存在由明亮的耀斑拱廊连接的双耀斑带。有趣的是，这个部分喷发事件具有微波对应，其时空演变与Hα和EUV中看到的灯丝密切相关。微波源的光谱特性与非热回旋同步辐射一致。利用空间分辨的微波光谱分析，我们得到了沿线材脊柱的磁场强度，从线材顶端到线材腿的磁场强度在600 ~ 1400高斯之间。结果与根据耀斑前光球磁图推断的非线性无力磁模型吻合较好。我们得出结论，爆发细丝的微波对应可能是由于耀斑加速的电子随着新重新连接的磁力线注入到细丝所在的磁通量绳腔中。
Magnetic flux ropes are the centerpiece of solar eruptions. Direct measurements for the magnetic field of flux ropes are crucial for understanding the triggering and energy release processes, yet they remain heretofore elusive. Here we report microwave imaging spectroscopy observations of an M1.4-class solar flare that occurred on 2017 September 6, using data obtained by the Expanded Owens Valley Solar Array. This flare event is associated with a partial eruption of a twisted filament observed in Hα by the Goode Solar Telescope at the Big Bear Solar Observatory. The extreme ultraviolet (EUV) and X-ray signatures of the event are generally consistent with the standard scenario of eruptive flares, with the presence of double flare ribbons connected by a bright flare arcade. Intriguingly, this partial eruption event features a microwave counterpart, whose spatial and temporal evolution closely follow the filament seen in Hα and EUV. The spectral properties of the microwave source are consistent with nonthermal gyrosynchrotron radiation. Using spatially resolved microwave spectral analysis, we derive the magnetic field strength along the filament spine, which ranges from 600 to 1400 Gauss from its apex to the legs. The results agree well with the nonlinear force-free magnetic model extrapolated from the preflare photospheric magnetogram. We conclude that the microwave counterpart of the erupting filament is likely due to flare-accelerated electrons injected into the filament-hosting magnetic flux rope cavity following the newly reconnected magnetic field lines.