Meterwave observations of a coronal hole

摘要: We present meterwave maps showing a coronal hole at 30.9, 50.0, and 73.8 MHz using the Clark Lake Radioheliograph in October 1984. The seen against disk all three frequencies shows interesting similarities to, significant differences from its optical signatures He i λl10830 spectroheliograms. Using model of holes by Dulk et al. (1977) we derive electron density radio observations brightness temperature. discrepancy between value derived Skylab EUV data that computed our is even larger than 's comparison similar higher frequencies.