Coronal mass ejections (CMEs) are large-scale eruptions of ionized gas (or plasma) from the Sun. The ejected material of a CME is associated with strong magnetic fields, which can cause substantial geomagnetic storms at Earth that enhance the radiation space environment and affect global communications and geolocation. Remote-sensing techniques such as Faraday rotation (FR), the rotation of the plane of polarization of linearly polarized radiation as it propagates through a magnetized plasma, can provide unique insights into the plasma density and magnetic-field structure of CMEs. FR provides information on the orientation of a CME’s magnetic field and can potentially be used to determine this orientation well before a CME reaches Earth (Liu et al., 2007). Further, Faraday-rotation observations of a source near the Sun can provide information on the plasma structure of a CME shortly after launch, potentially shedding light on the initiation process.
In this paper, we present the results of FR observations made using the radio galaxies (J2000 Right Ascension and Declination) 0842+1835, 0843+1547, and 0900+1832, which were occulted by CMEs on 2 August 2012, and use simultaneous Thomson-scattering brightness (TSB) data to independently determine the plasma-density structure through the occulting CMEs.
Data Analysis and Results
All radio ...