On the Relation of Brightness Temperatures in Coronal Holes at 5.7 and 17 GHz

From the analysis of simultaneous observations with the Siberian Solar Radio Telescope and Nobeyama Radioheliograph we show that coronal holes are not uniform. In particular, in coronal holes small-scale features exist with anticorrelating brightness temperatures at 5.7 and 17GHz. The features are disposed radially, which suggests radial heat transfer in them. We propose that the favorable heating mechanism within those features is