Pulsations of microwave emission from a solar flare in a twisted loop caused by intrinsic MHD oscillations

Abstract

We present results revealing microwave pulsations produced in a model of a flaring twisted solar coronal loop, without any external oscillatory driver. Two types of oscillations are identified: slowly-decaying oscillations with a period of about 70-75s and amplitude of about 5-10% seen in loops both with and without energetic electrons, and oscillations with period of about 40s and amplitude of a few tens of percent observed only in loops with energetic electrons for about 100s after onset of fast energy release. We interpret the longer-period oscillations as the result of a standing kink mode modulating the average magnetic field strength in the loop, whilst the short-period intermittent oscillations associated with energetic electrons are likely to be produced by fast variations of the electric field which produces energetic electrons in this scenario. The slowly-decaying oscillations can explain the quasi-periodic pulsations often observed in the flaring corona.

To be published in MNRAS

References in corpus (6)

• Quasi-periodic pulsations in solar and stellar flares: an overview of recent results
• Particle acceleration and transport in reconnecting twisted loops in a stratified atmosphere
• Persistent Quasi-Periodic Pulsations During a Large X-Class Solar Flare
• A blueprint of state-of-the-art techniques for detecting quasi-periodic pulsations in solar and stellar flares
• Predicting the time variation of radio emission from MHD simulations of a flaring T-Tauri star
• Probing Twisted Magnetic Field Using Microwave Observations in an M Class Solar Flare on 11 February, 2014

Cited by in corpus (4)

• Oscillatory reconnection and waves driven by merging magnetic flux ropes in solar flares
• Particle acceleration and their escape into the heliosphere in solar flares with open magnetic field
• The effects of resistivity on oscillatory reconnection and consequences for solar flare Quasi Periodic Pulsations
• Microwave response to kink oscillations of a plasma slab