The First Low-frequency Radio Observations of the Solar Corona on ≈200 km Long Interferometer Baseline

Abstract

The angular size of the smallest, compact radio source that can be observed in the solar atmosphere is one of the intriguing questions in low-frequency radio astronomy. This is important to understand density turbulence in the solar corona and the related angular broadening of the radio source sizes. We used a two-element interferometer with a baseline length of ≈200 km, operating at ≈53 MHz to infer the above limit. Our results indicate that radio sources of angular size ≤15'' exist in the solar corona, where radio emission at the above frequency also originates.