Low-frequency radio observations of the solar corona with arcminute angular resolution: implications for coronal turbulence and weak energy releases

Abstract

We report on the first long baseline interferometer (length ≈8 km) observations of the solar corona at 37 MHz that were carried out recently with an angular resolution of ≈1'. The results indicate that, (1) discrete radio sources of the aforesaid angular size or even lesser are present in the solar corona from where radiation at the above frequency originates. This constrains the angular broadening of radio sources at low frequencies due to scattering by density turbulence in the solar corona; and (2) the observed sources in the present case correspond to the weakest energy releases in the solar atmosphere reported so far.