论文标题
在新真空太阳能望远镜观察到的黑子中传播缓慢的香肠波
Propagating Slow Sausage Waves in a Sunspot Observed by the New Vacuum Solar Telescope
论文作者
论文摘要
黑子是用于多种磁性水动力波的理想波导，它在上层大气中载有大量能量，可用作探测黑子的磁性和热结构的工具。在这项研究中，我们使用了新的真空太阳能望远镜，并同时使用TIO（7058 $ \ pm $10Å）和H $_α$（6562 $ \ pm $2.5Å）的高分辨率图像序列。我们提取了Sunspot Umbra的面积和总发射强度变化，并通过同步转换分析了信号。我们发现面积和排放强度随三分钟和五分钟的周期性而变化。此外，该面积和强度相互相相振荡，这一事实在TIO和H $_α$数据中均存在。我们将此振荡信号解释为传播慢的香肠波。传播速度估计约为8 km $ \ cdot $ s $^{ - 1} $。我们推断，这个黑子的雨伞的温度可能低至2800--3500K。
A sunspot is an ideal waveguide for a variety of magnetohydrodynamic waves, which carry a significant amount of energy to the upper atmosphere and could be used as a tool to probe magnetic and thermal structure of a sunspot. In this study, we used the New Vacuum Solar Telescope and took high-resolution image sequences simultaneously in both TiO (7058$\pm$10 Å) and H$_α$ (6562$\pm$2.5 Å) bandpasses. We extracted the area and total emission intensity variations of sunspot umbra and analyzed the signals with synchrosqueezing transform. We found that the area and emission intensity varied with both three and five minute periodicity. Moreover, the area and intensity oscillated in phase with each other, this fact hold in both TiO and H$_α$ data. We interpret this oscillatory signal as propagating slow sausage wave. The propagation speed is estimated at about 8 km$\cdot$s$^{-1}$. We infer that this sunspot's umbra could have temperature as low as 2800--3500 K.
