论文标题
通过取消磁通量的太阳等离子体加热的观察性测试
An Observational Test of Solar Plasma Heating by Magnetic Flux Cancellation
论文作者
论文摘要
最近的观察结果表明，取消磁通量可能在加热太阳的上层大气（Colomosphere，过渡区，电晕）中起着至关重要的作用。在这里，我们打算验证一个分析模型，以进行磁重新连接和随之而来的冠状加热，这是由一对相反极性的收敛和取消磁通量驱动的。在此测试中，我们分析了在5.2小时的目标间隔内，在安静的互联网区域中，在安静的Internetwork区域中，小规模通量取消事件的光球磁场和多波长UV/EUV观察结果。观察到的取消事件在光球和红移多普勒速度上表现出了两个相对的磁贴在目标间隔上始终如一的磁力速度（下四），这两种极性的磁通量以10 $^{15} $^{15} $ mx s $^{-1 $^{-1} $降低。还观察到几种冲动的EUV亮丽，具有差分发射度量值在1.6-2.0 mk处达到峰值，在拱廊的形状中也观察到，其两个脚步固定在两个斑块中。估计在通量取消区域中释放的磁能速率在（0.2-1）$ \ times $ 10 $^{24} $ erg s $^{ - 1} $的范围内，这可以满足先前报道的安静的sun corona的先前报道的加热率。最后，在高于2.0 mk的温度下，估计电子的辐射能损失速率清楚地显示了磁释放速率的短期（几至几十分钟）的变化和长期（几个小时）的趋势。所有这些观察结果都支持了通过通量取消在太阳大气中调查的重新连接模型的有效性。
Recent observations suggest that magnetic flux cancellation may play a crucial role in heating the Sun's upper atmosphere (chromosphere, transition region, corona). Here, we intended to validate an analytic model for magnetic reconnection and consequent coronal heating, driven by a pair of converging and cancelling magnetic flux sources of opposite polarities. For this test, we analyzed photospheric magnetic field and multi-wavelength UV/EUV observations of a small-scale flux cancellation event in a quiet-Sun internetwork region over a target interval of 5.2 hr. The observed cancellation event exhibits a converging motion of two opposite-polarity magnetic patches on the photosphere and red-shifted Doppler velocities (downflows) therein consistently over the target interval, with a decrease in magnetic flux of both polarities at a rate of 10$^{15}$ Mx s$^{-1}$. Several impulsive EUV brightenings, with differential emission measure values peaked at 1.6-2.0 MK, are also observed in the shape of arcades with their two footpoints anchored in the two patches. The rate of magnetic energy released as heat at the flux cancellation region is estimated to be in the range of (0.2-1)$\times$10$^{24}$ erg s$^{-1}$ over the target interval, which can satisfy the requirement of previously reported heating rates for the quiet-Sun corona. Finally, both short-term (a few to several tens of minutes) variations and long-term (a few hours) trends in the magnetic energy release rate are clearly shown in the estimated rate of radiative energy loss of electrons at temperatures above 2.0 MK. All these observational findings support the validity of the investigated reconnection model for plasma heating in the upper solar atmosphere by flux cancellation.
