论文标题
通过快速变化的颗粒激发冲动波动
Impulsive wave excitation by rapidly changing granules
论文作者
论文摘要
尚不完全了解在太阳的内部和大气中如何激发磁性水动力波。传统上,内部的动荡对流被认为是安静的太阳中的波动激发源。在过去的几十年中,在光球中的晶间车道中观察到的声学事件已成为波动源的强大候选者。在这里,我们报告了新型事件对波动激发的观察结果:快速变化的颗粒。我们的观察结果是在H $α$和CA II 8542 $ \ UNICODE {XC5} $ LINE和TIO 7057 $ \ UNICODE {XC5} $宽带过滤器成像器的1.6 M GODE SOLAR TELESCOPE的Big Bear Bearer solar观察的1.6 M GODE SOLAR IMAR中。我们确定了互联网工作区域中经历快速动态变化的颗粒,例如崩溃(事件1),碎片(事件2)或淹没(事件3)。在光电图像中,这些颗粒变得比相邻的颗粒更暗。颗粒的快速变化后,在光球和色球层中检测到瞬时振荡。在事件1的情况下,振荡的主要周期在光球中接近4.2分钟,在色球圈中为3.8分钟。此外,在CA II $ - $ 0.5 $ \ UNICODE {XC5} $栅格图像中,我们在迅速变化的颗粒的位置观察到被视为冲击波表现的位置的重复亮丽。根据我们的结果,我们建议颗粒的动态变化可以在宁静的太阳中产生向上传播的声波,最终形成冲击。
It is not yet fully understood how magnetohydrodynamic waves in the interior and atmosphere of the Sun are excited. Traditionally, turbulent convection in the interior is considered to be the source of wave excitation in the quiet Sun. Over the last few decades, acoustic events observed in the intergranular lanes in the photosphere have emerged as a strong candidate for a wave excitation source. Here we report our observations of wave excitation by a new type of event: rapidly changing granules. Our observations were carried out with the Fast Imaging Solar Spectrograph in the H$α$ and Ca II 8542 $\unicode{xC5}$ lines and the TiO 7057 $\unicode{xC5}$ broadband filter imager of the 1.6 m Goode Solar Telescope at the Big Bear Solar Observatory. We identify granules in the internetwork region that undergo rapid dynamic changes such as collapse (event 1), fragmentation (event 2), or submergence (event 3). In the photospheric images, these granules become significantly darker than neighboring granules. Following the granules' rapid changes, transient oscillations are detected in the photospheric and chromospheric layers. In the case of event 1, the dominant period of the oscillations is close to 4.2 min in the photosphere and 3.8 min in the chromosphere. Moreover, in the Ca II$-$0.5 $\unicode{xC5}$ raster image, we observe repetitive brightenings in the location of the rapidly changing granules that are considered the manifestation of shock waves. Based on our results, we suggest that dynamic changes of granules can generate upward-propagating acoustic waves in the quiet Sun that ultimately develop into shocks.