Faraday Rotation Methods to Detect Coronal Currents and MHD Wave Activity

Abstract

Faraday rotation (FR) observations of the solar wind at heliocentric distances < 6 solar radii are critical for addressing questions such as "How is the solar wind accelerated?" and "What is the origin and evolution of the meso-scale plasma and magnetic field structure of the solar wind?" In particular, differential FR (DFR) can be used to detect electric currents and short-timescale FR fluctuations (FRF) can provide information on magnetohydrodynamic (MHD) wave activity. In order for future radio remote-sensing observations to take full advantage of these measurement methods, we recommend: developing the capability to probe the corona using the Galactic synchrotron background; equipping future spacecraft with linearly polarized radio communication systems; equipping future spacecraft with multi-frequency downlink antennas; and designing future missions around multiple spacecraft flying in close formation.Faraday Rotation Methods to Detect Coronal Currents and MHD Wave Activity Kooi et al.