CRITICAL EARLY DKIST SCIENCE: FINE STRUCTURE IN UNI-POLAR MAGNETIC FIELDS

Catholic University Of America, Washington DC

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This Daniel K. Inouye Solar Telescope (DKIST) First Science project focuses on features in the Sun’s outer atmosphere, the corona, called coronal plumes. They are long and narrow, but bright and tend to be seen near coronal holes (dark and cool regions in the corona). Plumes are considered to be one of the main sources of the interplanetary magnetic field and solar wind. This project will use the unprecedented magnetic sensitivity of DKIST to examine these features, which are believed to have stronger magnetic fields than previous observations indicated. This project addresses one of the DKIST Critical Science Plan Research Areas. Because of the implications of this work for the solar wind and interplanetary magnetic field, the broader impacts include connection to the National Science and Technology Council’s 2019 Space Weather Strategy and Action Plan. This project carries out the basic research in the space environment and drivers of space weather. This project also supports a student intern from a community college and a minority serving institution. Preliminary studies have found that extreme-ultraviolet images from NASA’s Solar Dynamics Observatory (SDO) often show small, loop-like features embedded inside active region plages and at the footpoints of coronal hole plumes even though no minority-polarity flux is visible in the corresponding SDO’s Helioseismic and Magnetic Imager (HMI) magnetograms. This suggests that the HMI magnetograms may be substantially underestimating the amount of minority flux inside plages and the strong underlying network. The research team will use high resolution magnetic field data from the DKIST to address this puzzling result. DKIST is particularly well suited for these challenging observations as it is expected to deliver solar magnetic field measurements with superior spatial resolution and the highest possible magnetic sensitivity. The Diffraction Limited Near Infrared Spectro-polarimeter (DL-NIRSP) will provide photospheric magnetic field information in the near infrared and the Visible Broadband Imager (VBI) will record images from the DKIST telescope at the highest possible spatial and temporal resolution at wavelengths in the range from 390 nm to 860 nm This will be used to find where the loops are embedded within the larger-scale magnetic field and flow field. Observational evidence of the existence of this missing small-scale mixed polarity flux will have major implications for models of coronal loops and, more generally, solar and stellar coronal heating and solar wind acceleration. 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.