论文标题
快速冠状质量排斥的偏振学研究
Polarimetric Studies of a Fast Coronal Mass Ejection
论文作者
论文摘要
在这项工作中，我们对COR1和COR2仪器在船上太阳陆地关系天文台（立体声）任务进行了一项偏光研究，对2012年7月12日观察到的快速和宽阔的冠状质量弹出（CME）。从地球的角度观察到，CME源区域是X1.4耀斑位于太阳能磁盘上的S15W01。 CME的位置源自3D渐变的圆柱形壳（GCS）重建方法，约为S18W00，在2.5太阳RADII和5.7 Solar Radii时，S07W00的位置在S18W00左右，这意味着CME在Corona向外传播的同时偏向赤道。 CME的前沿的投影速度也从下电晕的200 km S $^{ - 1} $演变为Cor2视图中的1000 km S $^{ - 1} $。 CME的极化程度约为65％，但在某些CME地区可能高达80％。 CME显示了极化角度偏离切向角度的偏差，范围为10 $^\ Circ $ -15 $^\ Circ $（或更多）。我们的分析表明，这主要是由于以下事实：三个极化图像的序列不是同时从偏振参数中得出的，而是在几秒钟的时间内差异。在此时间间隔中，CME在仪器的FOV中至少通过两个像素移动，而这种位移会导致极化参数（极化程度，极化角度等）的不确定性。我们提出了一些前进的步骤，以改善极化的推导。这项研究对于分析具有极化能力的工具的未来数据很重要。
In this work we performed a polarimetric study of a fast and wide coronal mass ejection (CME) observed on 12 July 2012 by the COR1 and COR2 instruments onboard Solar TErrestrial RElations Observatory (STEREO) mission. The CME source region was an X1.4 flare located at approximately S15W01 on the solar disk as observed from the Earth's perspective. The position of the CME as derived from the 3D Graduated Cylindrical Shell (GCS) reconstruction method was at around S18W00 at 2.5 solar radii and S07W00 at 5.7 solar radii, meaning that the CME was deflected towards the Equator while propagating outward in the corona. The projected speed of the leading edge of the CME also evolved from around 200 km s$^{-1}$ in the lower corona to around 1000 km s$^{-1}$ in the COR2 field of view. The degree of polarisation of the CME is around 65 % but it can go as high as 80 % in some CME regions. The CME showed deviation of the polarisation angle from the tangential in the range of 10$^\circ$ - 15$^\circ$ (or more). Our analysis showed that this is mostly due to the fact that the sequence of three polarised images from where the polarised parameters are derived is not taken simultaneously, but at a difference of few seconds in time. In this interval of time, the CME is moving by at least two pixels in the FOV of the instruments and this displacement results in uncertainties in the polarisation parameters (degree of polarisation, polarisation angle, etc.). We propose some steps forward to improve the derivation of the polarisation. This study is important for analysing the future data from instruments with polarisation capabilities.
