Type II radio emission predictions: Sources of coronal and interplanetary spectral structure

Abstract

We extend a model for type II radio bursts to investigate emission from the quiet corona, as well as the emission relating to structures in the corona and interplanetary medium. The most notable effect for the quiet corona is the weakening or disappearance of emission near a peak in the heliocentric Alfvèn speed profile. By inserting various structures into the coronal and interplanetary plasma, most observed type II features are produced. Specifically, multiple‐lane events, differing frequency drift rates, emission which turns on and off, and narrowband and broadband emission can be produced.