Type III Solar Radio Burst Profiles, Directionality, and Wave Scattering Model

Abstract:

We use joint observations of solar Type III radio bursts by Wind/Waves, STEREO-A/WAVES, and Parker/FIELDS/RFS to study their properties and create a multi-parameter model. The observed intensities are partially related to the distance from the spacecraft to the radio burst source (as a function of frequency). Arrival directions of the radio emission at the spacecraft, and relative timing of the profiles can be used to determine the location of the burst as a function of frequency, which has been performed and published many times, e.g., M.J. Reiner et al. (1998), M.J. Reiner et al. (2009), S.T. Badman et al. (2018). In the current solar cycle, a new data element is the observations from Parker Solar Probe (PSP) much closer to the Sun, down to ~0.3 AU, compared to the other spacecraft at ~1 AU. The PSP FIELDS Radio Frequency Spectrometer (RFS) data provide a unique constraint on the burst parameters. The properties that are the focus of our model are the typical profile forms of the type III bursts, the relative intensity observed as a function of angle relative to several parameters, and the consequences of radio wave scattering based on the typical solar wind and the possible location of observed interplanetary medium structures between the radio source and the spacecraft.