Langmuir-wave conversion as the explanation of moving type IV solar meter-wave radio outbursts

Abstract

The properties of moving type IV solar radio outbursts observed with the Culgoora radioheliograph and radiospectrograph suggest that these outbursts -even those which rise to great coronal heights -originate through Langmuir-wave conversion. This implies that coronal densities are sometimes greatly enhanced.

Modulations of broad-band radio continua and X-ray emissions in the large X-ray flare on 03 November 2003

“…Boischot and Denisse, 1957) or plasma emission (see e.g. Duncan, 1981;Trottet et al, 1981). For the present flare, the radio spectrum observed from 09:57 UT rather suggests that the continuum at 327 MHz is produced by gyrosynchrotron emission of energetic electrons.…”

An Estimate of the Magnetic Field Strength Associated With a Solar Coronal Mass Ejection From Low Frequency Radio Observations

“…One of the reasons for this is the non-availability of simultaneous white light and radio observations close to the Sun (r 2 R ⊙ ), and the relatively rare occurrence of the type IVm bursts White (2007). The bursts have been explained using either second harmonic plasma emission (Duncan 1981;Stewart et al 1982b;Gopalswamy & Kundu 1989b;Kundu et al 1989;Ramesh et al 2013) or optically thin non-thermal gyro-synchrotron emission (Gopalswamy & Kundu 1989a;Bastian & Gary 1997;Bastian et al 2001;Maia et al 2007;Tun & Vourlidas 2013) in the past. Using simultaneous whitelight, radio heliograph, radio polarimeter and radio spectral observations we have presented arguments to show that the type IVm burst associated with the 'halo' CME event of 2013 March 15 can be explained on the basis of non-thermal gyro-synchrotron emission and estimated the magnetic field strength near the source region of the burst.…”

The dynamics of an erupting prominence

“…They are emitted by suprathermal electrons through either the gyrosynchrotron process (Dulk 1973) or plasma emission (Robinson 1978;Duncan 1981;Trottet et al 1981). The radio sources are characterised by systematic outward motions over distances up to several solar radii, and are often associated with prominence eruptions (cf.…”