Electron Densities in the Solar Corona Measured Simultaneously in the Extreme Ultraviolet and Infrared
Electron Densities in the Solar Corona Measured Simultaneously in the Extreme Ultraviolet and Infrared
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DOI：
10.3847/1538-4357/abcd91
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发表时间：
2020-11
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通讯作者：
J. Dudík;G. del Zanna;J. Rybák;Juraj Lörinčík;E. Dzifčáková;H. Mason;S. Tomczyk;M. Galloy
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文献类型：
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作者：
J. Dudík;G. del Zanna;J. Rybák;Juraj Lörinčík;E. Dzifčáková;H. Mason;S. Tomczyk;M. Galloy
电子密度的精确测量是确定日冕等离子体性质的关键。我们比较诊断的电子密度从Fe XIII线观察到的极紫外成像光谱仪（EIS）船上的日出使命与近红外（NIR）测量提供的地面日冕多通道偏振仪（CoMP）。为了做到这一点，发射率比方法的基础上所有可用的观测线的Fe xiii的EIS和CoMP。EIS诊断进一步补充的结果从Fe xii线。我们发现极好的协议，在10%以内，从极紫外线和近红外线测量的电子密度之间。在选择用于详细分析的五个区域中，我们获得log（Ne [cm−3]）= 8.2-8.6的电子密度。在可用的情况下，背景减除对诊断具有显著影响，特别是对NIR线，其中环路贡献小于沿视线沿着测量的强度的四分之一。对于近红外线，我们发现线中心强度不受仪器内杂散光的影响，并建议将其用于密度诊断。的Fe XIII近红外线的测量代表了一个可行的方法，密度诊断使用地基仪器。
Accurate measurements of electron density are critical for determination of the plasma properties in the solar corona. We compare the electron densities diagnosed from Fe xiii lines observed by the Extreme-Ultraviolet Imaging Spectrometer (EIS) onboard the Hinode mission with the near-infrared (NIR) measurements provided by the ground-based Coronal Multichannel Polarimeter (CoMP). To do that, the emissivity-ratio method based on all available observed lines of Fe xiii is used for both EIS and CoMP. The EIS diagnostics is further supplemented by the results from Fe xii lines. We find excellent agreement, within 10%, between the electron densities measured from both extreme-ultraviolet and NIR lines. In the five regions selected for detailed analysis, we obtain electron densities of log(N e [cm−3]) = 8.2–8.6. Where available, the background subtraction has a significant impact on the diagnostics, especially on the NIR lines, where the loop contributes less than a quarter of the intensity measured along the line of sight. For the NIR lines, we find that the line center intensities are not affected by stray light within the instrument, and recommend using these for density diagnostics. The measurements of the Fe xiii NIR lines represent a viable method for density diagnostics using ground-based instrumentation.