Unusually low coronal radio emission at the solar minimum

摘要: We present two-dimensional observations of the quiet Sun at 73.8, 50.0, and 38.5 MHz obtained with Clark Lake Radioheliograph during sunspot minimum period September 1986. The observed peak brightness temperatures entire are found to be extremely low, lying in range (0.6 × 105 K − 2.5 K). It is shown that these low values cannot explained by generally adopted models for N e T a homogeneous corona. effect scattering random density fluctuations introduced order decrease predicted b . value computed as function relative r.m.s. e = <ΔN >/N ; it ɛ should from 0.07 0.19, 0.1 0.25, 0.15 0.35, respectively, 38.5, 73.8 MHz, explain temperatures.