High-Resolution Observations of Alfvenic Waves in the Solar Corona: Critical Early DKIST Science

太阳物理学中最持久的谜团之一是日冕加热问题。日冕的温度超过一百万开。它唯一重要的热源，太阳光球层，只有几千开尔文的温度。一个新兴的模型表明，能量可能通过太阳/行星际磁场中的“阿尔芬波”以非热的方式沉积到日冕中。这个研究小组将通过使用新委托的丹尼尔K. Inouye太阳望远镜（DKIST）。这项工作将用于培养博士后研究人员，并为本科生提供研究机会。此外，参与者将通过哥伦比亚大学举办的公开讲座和观星计划进行外展。该团队将观察日冕以及日冕洞，以测试日冕加热的阿尔芬波耗散模型的四个不同方面。首先，他们将使用DKIST的Cryo-NIRSP仪器观察到的光谱发射线的宽度来检查日冕洞中的阿尔芬波阻尼。接下来，该团队将使用Cryo-NIRSP测量日冕中Alfven波的多普勒频移来检查波反射。第三，他们将使用DKIST的DL-NIRSP仪器进行高空间分辨率成像光谱学，以检查日冕内部的阿尔芬波结构，并确定可能存在哪些波模式（扭结，扭转）。第四，他们将使用DL-NIRSP仪器来检查阿尔芬波的空间范围（“垂直波长”），以确定被给定波加速的粒子的特征区域。这类测量只有在DL-NIRSP的高空间分辨率下才有可能。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

One of the most enduring mysteries in solar physics is the coronal heating problem. The solar corona has temperatures of over a million kelvins. Its only significant heat source, the solar photosphere, has a temperature of only a few thousand kelvins. An emerging model suggests that energy may be deposited into the corona nonthermally through “Alfven waves” in the solar/interplanetary magnetic field. This team will fully test this model by making observations of Alfven waves in the solar corona using the newly-commissioned Daniel K. Inouye Solar Telescope (DKIST). The work will be used to train a postdoctoral researcher and will provide research opportunities for undergraduate students. In addition, participants will conduct outreach through a public lecture and stargazing program conducted by Columbia University. The team will observe the Solar corona as well as coronal holes to test four different aspects of the Alfven wave dissipation model of coronal heating. First, they will use widths of spectroscopic emission lines as observed by DKIST’s Cryo-NIRSP instrument to examine Alfven wave damping in coronal holes. Next, the team will use Cryo-NIRSP measurements of Doppler shifting of Alfven waves in the corona to examine wave reflection. Third, they will conduct high-spatial-resolution imaging spectroscopy with DKIST’s DL-NIRSP instrument to examine the Alfven wave structure inside the corona, and determining which wave modes (kink, torsional) might be present. Fourth, they will use the DL-NIRSP instrument to examine the spatial extent (‘perpendicular wavelength’) of Alfven waves to determine the characteristic region of particles accelerated by a given wave. These kinds of measurements are only possible because of the high spatial resolution of DL- NIRSP.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.