A study of filament transition sheath from radio observations

✍ Scribed by A. Pramesh Rao; M. R. Kundu

• Publisher: Springer
• Year: 1977
• Tongue: English
• Weight: 925 KB
• Volume: 55
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00150882

✦ Synopsis

We have observed an Ha dark filament at 8, 15, and22 GHz and derived the radio spectrum of the flament. We suggest that the filament has to be optically thick at radio frequencies and that the observed spectrum is due to the presence of a transition sheath surrounding the filament. We examine a model for the transition sheath in which the energy radiated away is balanced by the conduction of heat from the corona, and show that the radio observations indicate that little or no thermal energy is conducted into the main body of the filament. We compare the model with ultraviolet observations of filaments and discuss how the discrepancies can be removed.