论文标题
染色体和过渡区中黑子冲击波的动力学
Dynamics of Sunspot Shock Waves in the Chromosphere and Transition Region
论文作者
论文摘要
我们研究了使用界面区域成像光谱仪（IRIS）的光谱观测来研究在黑子的umbra中观察到的冲击波动力学。电击的存在显着变形了Mg II，C II和SI IV的光谱线的形状。我们发现C II1335.66Å和Si IV1393.75Å显示了双峰的轮廓，后来将变为单个峰。但是，Mg II H2803.53Å线首先显示了平面轮廓，这些轮廓变为双峰，然后是单个峰。为了研究冲击动力学，我们通过拟合两个高斯人将冲击成分与光谱分离。我们发现，电击的寿命在Mg II H2803.53Å线中最大。此外，等离子体运动既显示冲击的加速度和减速阶段。然而，在C II1335.66Å和Si IV1393.75Å中，仅观察到减速阶段。我们观察到所有三种光谱线的最大蓝光与减速的最大蓝光之间的相关性。我们发现由于Mg II和C II（SI IV）的冲击而导致强度的正相关（负）。这暗示着电击在C II中首先放大，然后在与Si IV相对应的高度范围下降。这些结果可能表明冲击在C II的形成高度上方的耗散，而冲击可能在下slo的上铬球和过渡区的动力学中具有重要作用。
We study the dynamics of shock waves observed in the umbra of a sunspot using the spectroscopic observations from the Interface Region Imaging Spectrometer (IRIS). The presence of the shock significantly deforms the shape of the spectral lines of Mg II , C II , and Si IV . We found that C II 1335.66 Å and Si IV 1393.75 Å show double-peaked profiles that change to a single peak later on. However, the Mg II h 2803.53 Å line first shows flat-top profiles that change into double-peaked followed by the single peak. To study the shock dynamics, we isolate the shock component from the spectra by fitting two Gaussians. We find that the lifetime of the shock is largest in Mg II h 2803.53 Å line. Moreover, the plasma motion shows both acceleration and deceleration phase of the shock. Yet, in C II 1335.66 Å and Si IV 1393.75 Å, only deceleration phase is observed. We observe a strong correlation between the largest blueshift of the shock and deceleration for all three spectral lines. We find a positive (negative) correlation between intensities contributed due to the shocks in Mg II and C II (Si IV ). This is suggestive that the shocks are first amplified in C II , followed by a decline in the height range corresponding to Si IV . These results may indicate the dissipation of shocks above the formation height of C II , and the shocks may have important roles in the dynamics of the upper chromosphere and transition region above sunspots.
