STEREO

A 19-day solar radio burst: a corotating radio reservoir in the outer corona by Vratislav Krupar et al.

June 16, 2026

Solar radio astronomers are used to type IV bursts as the long afterglow of eruptive activity: broadband continua, often polarized, produced by energetic electrons trapped in post-eruption magnetic structures. But “long” usually means minutes to hours, sometimes longer in exceptional cases. The event reported by Krupar et al. 2026 changes that scale. A hectometric type IV continuum between about 0.5 and 3 MHz was observed over nearly 19 days, from […]

Interplanetary Type III radio Emission Locations determined from the Underlying Electron Exciter Beam Kinematics by Michael Reiner

May 26, 2026

Type III solar radio bursts, which appear as characteristic frequency-drifting features on radio dynamic spectra, are generated by energetic beams of electrons originating in solar active regions and propagating through the solar corona and interplanetary medium. The early low frequency spacecraft observations of interplanetary type III bursts prompted efforts to locate and track the observed radio source regions through the interplanetary medium. Without imaging capabilities on interplanetary spacecraft, a number […]

Multispacecraft Analysis and Modeling of Type III Radio Burst Exciter Deceleration in Inhomogeneous Heliospheric Plasma F. Azzolini et al.

November 11, 2025

Electron beams accelerated in solar flares and escaping from the Sun along open magnetic field lines can trigger intense radio emissions known as type III solar radio bursts. However, the propagation dynamics of these electrons is still poorly understood and observationally constrained (Dulk et al 1987, Krupar et al 2015). Historically, single-spacecraft measurements have suggested deceleration but suffered from large uncertainties due to unknown source position. By leveraging four spacecraft […]

Synchrotron or not – analysis of two-part type II bursts by Silja Pohjolainen

May 27, 2025

A distinct class of interplanetary (IP) type II bursts that show single-lane, wide-band diffuse emission has been identified, but how these bursts are formed is still unclear. The radio burst on June 17-18, 2003 was analysed by Bastian (2007) , who suggested that the wide-band and diffuse part of the burst (type II-S in Fig. 1) could be due to synchrotron emission. The later part of the burst (type II-P) […]

Multi-spacecraft Radio Observations Trace the Heliospheric Magnetic Field by D. L. Clarkson et al.

April 25, 2025

Solar flares accelerate energetic electrons that escape into interplanetary space, guided by the Parker spiral magnetic field, and are responsible for the generation of the interplanetary Type III solar radio bursts. With multiple spacecraft now in orbit around the Sun (see e.g. Musset et al 2021), we are in a unique position of observing the propagation of radio emission through the heliosphere from multiple vantage points. Recent study by Clarkson […]