日冕物质抛射相关的5303Å日冕发射线展宽的Aditya-L1/VELC观测
Aditya-L1/VELC observations of CME associated broadening of 5303Å coronal emission line
AI总结：
通过Aditya-L1/VELC光谱观测日冕物质抛射前后5303Å日冕发射线宽度变化，研究‘边缘’日冕物质抛射，发现线宽变化及功率谱密度分布呈幂律行为，揭示线宽变化原因。
摘要：
我们展示了Aditya-L1/VELC对日冕物质抛射（CMEs）前后5303Å日冕发射线宽度的光谱观测，这些CMEs表现出日冕变暗。观测的坐视模式使我们能够研究2024年7月16日和2024年8月5日观测到的‘边缘’CMEs的线宽变化。两个案例中，CME前阶段的发射线宽度高于热值。CME开始后，2024年7月16日线宽进一步增加约15%，2024年8月5日增加约7%。我们发现两个事件的线宽功率谱密度（PSD）分布呈现幂律行为。CME前后测量的PSD斜率几乎相同，接近-5/3的Kolmogorov斜率。结果表明，观测到的CME前后5303Å发射线大于热宽度主要是由于湍流。两个案例中CME开始后线宽的额外增加可能是由于CME相关日冕变暗和随后的日冕磁场重新配置导致的湍流增强。
英文摘要：
We present Aditya-L1/VELC spectroscopic observations of 5303Å coronal emission line widths before and after coronal mass ejections (CMEs) which showed coronal dimming. The sit \& stare mode of observations enabled us to study the changes in the line widths for the `limb' CMEs noticed on 16 July 2024 and 05 August 2024. The emission line widths during the pre-CME phase are higher than the thermal values in both the cases. After the onset of the CMEs, the widths increased further by ${\approx}15\%$ on 16 July 2024 and ${\approx}7\%$ on 05 August 2024. We find that the power spectral density (PSD) distributions of the line widths for the two events exhibits a power-law behavior. The PSD slopes, measured before and after the CMEs are nearly the same, and close to the Kolmogorov slope of ${-5/3}$. The results suggest that the observed larger than thermal width of the 5303Å emission line, before and after CMEs, is mostly due to turbulence. The additional increase in the line widths after the onset of the CMEs in both the cases are likely because of enhanced turbulence caused by the CME associated coronal dimmings and subsequent coronal magnetic field reconfiguration.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
