Nancay Radio Heliograph (NRH)

solar flare X-ray light-curves

Non-thermal energy release in the post-impulsive phase of the May 9, 2021 event by M. Zhang et al.

March 17, 2026

The acceleration of charged particles is an ubiquitous phenomenon in solar flares. Non-thermal electrons are especially probed by their hard X-ray (HXR) and radio emissions. Most flare analyses concern the impulsive flare phase, where the X-ray signatures are the most intense (i.e., the time range between the start and peak time of the soft X-ray burst).The post-impulsive phase of eruptive flares with its signatures of destabilization and the eruption of […]

Anisotropic density turbulence variation from the low corona to 1 au as deduced from solar radio observations by E. Kontar et al.

November 30, 2023

Density turbulence in the solar corona and solar wind is evident via the properties of solar radio bursts; angular scattering-broadening of extra-solar radio sources observed through the solar atmosphere, and can be measured in-situ in the solar wind. A viable density turbulence model should simultaneously explain all three types of density fluctuation observations. Solar radio bursts (e.g. Type I, II, III) observed below ~1 GHz are produced predominantly via plasma […]

Loss-cone instability modulation due to a magnetohydrodynamic sausage mode oscillation in the solar corona by E. P. Carley et al.*

May 12, 2020

Flare accelerated electrons emit light from X-rays to radio waves, which sometimes show highly regular and periodic intensity pulsations (Nakariakov et al. 2009). However, the processes that bring about these pulsations remains a hotly debated topic. The primary candidates are periodic magnetic reconnection, magnetohydrodynamic (MHD) oscillations, or some complex combination of both (Aschwanden et al. 1986, Nakariakov et al. 2006). Plasma dynamics of these processes can play out on timescales […]

Imaging spectroscopy of fiber bursts by C. Alissandrakis*

October 15, 2019

Fibers are short metric/decimetric bursts with a drift rate between type II and type III bursts, usually appearing in groups embedded in type IV continua. In most cases they show both absorption and emission ridges, the absorption having a slightly lower frequency than the emission. They are, most probably, manifestations of whistler-Langmuir wave interaction and they travel upwards along post flare loops (Kuijpers 1975). In a recent work (Bouratzis et […]

Variable Emission Mechanism of a Type IV Radio Burst by D. Morosan et al.*

April 23, 2019

Coronal mass ejections (CMEs) are sometimes accompanied by continuum emission at decimetric and metric wavelengths, called Type IV radio bursts. Of particular interest to determining CME properties are moving Type IV radio bursts, which are broadband radio sources moving outwards from the Sun. First studies suggested that moving Type IV bursts are emitted by synchrotron or gyro-synchrotron emitting electrons that are trapped inside CME loops (Dulk 1973). However, since their […]