How to Advance Studies of Coronal Faraday Rotation

Abstract

Detection of Faraday rotation (FR) is one of the best remote-sensing methods for probing the plasma structure, including the magnetic field, of the solar wind and coronal mass ejections (CMEs). FR is the rotation of the plane of polarization of linearly polarized radiation as it propagates through a magnetized plasma and provides information about the electron number density and the component of the magnetic field along the line of sight (LOS) to the observer. We outline several recommendations to continue developing FR methods, including: (1) equipping the next generation of spacecraft with linearly polarized, multi-frequency transmitters; (2) developing the capability to generate coronal FR sky maps with natural radio sources or the Galactic synchrotron background; (3) creating new methods to use current and future whitelight imagers to enhance coronal FR observations; (4) exploring the potential for space-based FR observations; and (5) training machine-learning algorithms to interpret coronal and CME FR observations, which could become a powerful new tool for space weather forecasting.