CESRA science nuggets

dynamic spectra

A Wide-Band High-Frequency Type-II Solar Radio Burst by Vasanth et al.

December 23, 2025

Type-II radio bursts are usually observed below 400 MHz with slowly-drifting narrow fundamental and/or harmonic bands. Events with starting frequencies higher than 400 MHz are rarely reported (e.g., Pohjolainen et al. 2008). Such high-frequency Type-IIs may stem from the CME interaction with surrounding dense structures in the corona, such as streamers, ray-like or loop structure, or from sources in the lower corona. Figure. 1. Dynamic spectrum of the high-frequency wide-band […]

First Robust Detection of Linear Polarization from Metric Solar Emissions: Challenging Established Paradigms by S. Dey et al.

December 9, 2025

Polarization measurements of solar radio emissions are key diagnostics of coronal plasma, magnetic fields, and propagation effects, and can provide additional constraints on the emission mechanisms. At meter wavelengths, circular polarization (CP) has long been exploited in solar radio studies, while linear polarization (LP) has been assumed to be absent. This view arose from the expectations that strong coronal Faraday rotation would completely depolarize LP within typical observational bandwidths and […]

New Instrument in Solar Flare Detection: A 50–55 GHz Millimeter-Wave Radiometer Spectrometer by X. Xu et al.

November 25, 2025

Solar flares, among the most intense explosive phenomena in the solar atmosphere, release vast amounts of energy in a short period, resulting in enhanced electromagnetic radiation across multiple bands. These events pose significant threats to Earth’s space environment and human activities in space. High-energy electrons accelerated during flares emit millimeter-wave radiation through gyrosynchrotron radiation, providing unique insights into the underlying magnetic fields and energy release processes (Fleishman et al 2018). […]

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 […]

Noise in Maps of the Sun at Radio Wavelengths by T. S. Bastian et al.

October 28, 2025

The Sun is a powerful source of radio emissions, so much so that – unlike most celestial sources – this emission dominates the system noise of many radio telescopes. The noise resulting from such sources is referred to as “self-noise”. Two recent papers discuss self-noise in maps of the Sun at radio frequencies formed using the techniques of Fourier synthesis imaging. Examples of radio telescopes that exploit this technique include […]