A coherent radiation mechanism for type IV solar radio bursts

✍ Scribed by G. S. Lakhina; B. Buti

• Publisher: Springer
• Year: 1985
• Tongue: English
• Weight: 515 KB
• Volume: 99
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00157312

✦ Synopsis

A new coherent radiation mechanism, involving nonlinear interaction of whistler solitons with upperhybrid waves, excited by energetic electrons of energies of 10 keV-100 keV, is proposed for type IV solar bursts of both moving (type IV M) and stationary (type IV S) types. We show that the type IV M bursts occur when the interaction of whistler solitons and upperhybrid waves takes place in the coronal transients whereas the type IV S bursts originate provided this interaction takes place in stationary loops where density has been increased. The emitted radiation is right-hand circularly polarized with ~100~ polarization. Increase of brightness temperature, Tb, at lower frequencies and also its decrease, at all frequencies, with the passage of time is predicted for type IV M bursts; this agrees fully with the observations. Furthermore, the decrease of Tb, with time for stationary type IV component, is easily explained if the source which supplies energetic electron to the loop, becomes weaker with time.