Radio, X-ray and extreme-ultraviolet observations of weak energy releases in the ‘quiet’ Sun
by Ramesh et. al.

2021-10-26 136 views

Small scale energy releases on the Sun e.g., flaring bright points, active region transient brightenings, etc. have been studied using X-ray and radio observations. The observations of low frequency radio type III bursts in associated with X-ray bright point flares (Kundu et. al. 1980) and coronal X-ray jets (Aurass et. al. 1994) indicated that the latter are capable of accelerating particles to non-thermal energies, as well as producing the heated […]

Anisotropic radio-wave scattering in the solar corona
Nicolina Chrysaphi et al.*

2019-11-26 447 views

Solar radio emission is produced in the turbulent medium of the solar atmosphere, and its observed properties (source position, size, time profile, polarization, etc.) are significantly affected by the propagation of the radio waves from the emitter to the observer. Scattering of radio waves on random density irregularities has long been recognized as an important process for the interpretation of radio source sizes (e.g., Steinberg et al. 1971), positions (e.g., […]

Solar Physics with the Square Kilometre Array
by A. Nindos et al.*

2019-08-13 545 views

Although solar physics is one of the most mature branches of astrophysics, the Sun confronts us with a large number of outstanding problems that are fundamental in nature.  These problems include the determination of the structure and dynamics of the solar atmosphere, the magnetic field evolution in the chromosphere and corona, coronal heating, the physics of impulsive energy release, energetic particle acceleration and transport, the physics of coronal mass ejections […]

Solar plasma radio emission and inertial Alfvén turbulence
by O. Lyubchyk et al.*

2017-09-26 556 views

We study the influence of kinetic-scale Alfvénic turbulence on the generation of plasma radio emission in the solar coronal regions where the plasma/magnetic pressure ratio $\beta $ is smaller than the electron/ion mass ratio $m_{e}/m_{i}$. The present study is motivated by the phenomenon of solar type I radio storms associated with the strong magnetic field of active regions. The measured brightness temperature of the type I storms can be up […]

High resolution observations of radio noise storms in the solar corona
by Prasad Subramanian and Claude Mercier

2016-09-06 994 views

The solar corona is a well known site for particle acceleration – examples range from spectacular large flares to the hard-to-observe nanoflares that are now a leading candidate for coronal heating. We focus here on radio noise storms, which are very commonplace instances of small electron acceleration episodes. Noise storm sources are relatively small (less than 1 arcmin) and vary over timescales shorter than a second. There can often be […]

High dynamic range solar radio images by combining visibilities from the Giant Meterwave Radio Telescope and the Nancay Radioheliograph
by Claude Mercier

2006-12-07 140 views

We present first results from an ongoing program of combining data from the Nancay Radioheliograph NRH and the Giant Meterwave Radio Telescope GMRT, to produce snapshot images of the Sun at meter wavelengths. The data processing includes a superposition of complex visibilities from NRH and GMRT, a Fourier Transform and a cleaning multi-scale algorithm. We show results from a simulation and an observation of a complex noise storm at 327 […]