Detection of Fast/Alfvén Magneto-Atmospheric-Gravity Waves in a Sunspot Chromosphere with DKIST/ViSP

Using the Daniel K. Inouye Solar Telescope (DKIST) Visible Spectro-Polarimeter (ViSP) instrument, we collected Science Verification data on May 8 2021. ViSP observed multiple layers of a sunspot atmosphere simultaneously, with an unprecedented spatial resolution of 0.02×0.041 arcsec. The spectropolarimetric raster observations exhibit prominent wave-like ‘ridge’ structures across an active region, lying nearly perpendicular to the (north to south) direction of slit movement. These ridges are visible in intensity, Doppler velocity, line width, linear polarization and line-of-sight (LOS) magnetic field measurements of the chromospheric Ca II 854.2 nm line. By employing a moving-slit-method, with a rastering slit speed of ~4 km/s the induced Doppler effect allows us to separate the slow- from the coupled fast/Alfvén-magneto-acoustic-gravity (MAG) waves owing to their distinct propagation speeds