EVIDENCE OF ELECTRON ACCELERATION AROUND THE RECONNECTION X-POINT IN A SOLAR FLARE
EVIDENCE OF ELECTRON ACCELERATION AROUND THE RECONNECTION X-POINT IN A SOLAR FLARE
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DOI：
10.1088/0004-637x/787/2/125
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
N. Narukage;M. Shimojo;T. Sakao
中科院分区：
文献类型：
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作者：
N. Narukage;M. Shimojo;T. Sakao
粒子加速是宇宙和空间等离子体中普遍存在的最重要的特征之一。在太阳的耀斑期间，它是最突出的，大量的电磁辐射和高能粒子通过日冕中等离子体粒子的加速被排入行星际空间。虽然人们已经很好地理解耀斑的能量是由磁重联机制提供的，这是基于空间望远镜在X射线和EUV中的观测，但由于耀斑日冕中的等离子体密度很低，在耀斑磁场中等离子体在哪里以及如何加速仍然是未知的。我们在这里报告的第一个观测识别的高能非热电子周围的点正在进行的磁重联（X点），与软X射线图像和非热电子的局部存在的位置确定的X点从成像光谱数据在两个微波频率。考虑到存在的重联流出，携带等离子体粒子和磁场从X点，我们确定的非热微波辐射周围的X点表明，电子被加速周围的重联X点。此外，X点周围的等离子体也被加热到10 MK。该事件的估计重新连接率为0.017。
Particle acceleration is one of the most significant features that are ubiquitous among space and cosmic plasmas. It is most prominent during flares in the case of the Sun, with which huge amounts of electromagnetic radiation and high-energy particles are expelled into the interplanetary space through acceleration of plasma particles in the corona. Though it has been well understood that energies of flares are supplied by the mechanism called magnetic reconnection based on the observations in X-rays and EUV with space telescopes, where and how in the flaring magnetic field plasmas are accelerated has remained unknown due to the low plasma density in the flaring corona. We here report the first observational identification of the energetic non-thermal electrons around the point of the ongoing magnetic reconnection (X-point), with the location of the X-point identified by soft X-ray imagery and the localized presence of non-thermal electrons identified from imaging-spectroscopic data at two microwave frequencies. Considering the existence of the reconnection outflows that carries both plasma particles and magnetic fields out from the X-point, our identified non-thermal microwave emissions around the X-point indicate that the electrons are accelerated around the reconnection X-point. Additionally, the plasma around the X-point was also thermally heated up to 10 MK. The estimated reconnection rate of this event is ∼0.017.