Modeling of gyrosynchrotron radio emission pulsations produced by MHD loop oscillations in solar flares

Abstract

A quantitative study of the observable radio signatures of the sausage, kink, and torsional MHD oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are than quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

ApJ, accepted

References in corpus (3)

• Broadband Quasi-Periodic Radio and X-ray Pulsations in a Solar Flare
• Broadband microwave burst produced by electron beams
• 3D simulations of gyrosynchrotron emission from mildly anisotropic nonuniform electron distributions in symmetric magnetic loops

Cited by in corpus (15)

• Solar science with the Atacama Large Millimeter/submillimeter Array - A new view of our Sun
• Quasi-periodic pulsations in solar and stellar flares: an overview of recent results
• Magnetohydrodynamic Fast Sausage Waves in the Solar Corona
• Line-of-sight geometrical and instrumental resolution effects on intensity perturbations by sausage modes
• Forward Modelling of Standing Slow Modes in Flaring Coronal Loops
• Microwave Imaging of Quasi-periodic Pulsations at Flare Current Sheet
• Simulations of Gyrosynchrotron Microwave Emission from an Oscillating 3D Magnetic Loop
• Multiple Regions of Nonthermal Quasi-Periodic Pulsations during the Impulsive Phase of a Solar Flare
• Excitation of Multi-periodic Kink Motions in Solar Flare Loops: Possible Application to Quasi-periodic Pulsations
• Quasi-periodic pulsations in extreme-ultraviolet brightenings
• Sources of Quasi-Periodic Pulses in the 18 August 2012 Flare
• Modulation of the solar microwave emission by sausage oscillations
• Influence of fine structures on gyrosynchrotron emission of flare loops modulated by sausage modes
• Modulation depth of the gyrosynchrotron emission as identifier of fundamental sausage modes
• Inferring the magnetic field asymmetry of solar flares from the degree of polarisation at millimetre wavelengths