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

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.