Solar and Heliospheric Observatory (SOHO) – Community of European Solar Radio Astronomers

Properties of High-Frequency Type II Radio Bursts and Their Relation to the Associated Coronal Mass Ejections
by A.C. Umuhire et al.*

2021-09-28 275 views

Type II radio bursts are slow-drifting and long-lasting radio emission produced by nonthermal electrons accelerated at shocks propagating through the solar corona and interplanetary medium (Nelson & Melrose, 1985). The accelerated electrons generate Langmuir waves, which get converted into electromagnetic radiation by the plasma emission mechanism first identified by Ginzburg & Zhelezniakov (1958). Currently, there is a common understanding that type II radio bursts are produced by shocks formed ahead […]

Coronal Mass Ejection-driven Type II solar radio burst structure with LOFAR and radio-wave scattering
by Nicolina Chrysaphi et al.*

2019-01-29 584 views

Coronal Mass Ejections (CMEs) are often viewed as the major drivers of space weather disturbances in the Sun-Earth system. Shocks driven by CMEs can excite radio emissions characterised by a slow frequency drift across dynamic spectra. These radio emissions are known as Type II solar radio bursts and can consist of two bands with a frequency ratio of 1:2. Each of these bands can split into two thinner sub-bands, a […]

An Extreme-ultraviolet Wave Generating Upward Secondary Waves in a Streamer-like Solar Structure
by Ruisheng Zheng et al.*

2018-08-07 336 views

Extreme-ultraviolet (EUV) waves are spectacular horizontally propagating disturbances in the low solar corona. If an EUV wave encounters an ambient coronal structure it may trigger another horizontal wave, which is always named a ‘secondary wave’ (SW). We present the first example of upward SWs in a streamer-like structure, a bright loop-like structure developing over an active region, after the passing of an EUV wave. The EUV wave was associated with […]