Quasi-Periodic Particle Acceleration in a Solar Flare

Abstract

A common feature of electromagnetic emission from solar flares is the presence of intensity pulsations that vary as a function of time. Known as quasi-periodic pulsations (QPPs), these variations in flux appear to include periodic components and characteristic time-scales. Here, we analyse a GOES M3.7 class flare exhibiting pronounced QPPs across a broad band of wavelengths using imaging and time-series analysis. We identify QPPs in the timeseries of X-ray, low frequency radio and EUV wavelengths using wavelet analysis, and localise the region of the flare site from which the QPPs originate via X-ray and EUV imaging. It was found that the pulsations within the 171 Ȧ, 1600 Ȧ, soft X-ray (SXR), and hard X-ray (HXR) light curves yielded similar periods of $\sim$122 s, $\sim$131s, $\sim$123 s, and $\sim$137 s, respectively, indicating a common progenitor. The low frequency radio emission at 2.5 MHz contained a longer period of $\sim$231 s. Imaging analysis indicates that the location of the X-ray and EUV pulsations originates from a HXR footpoint linked to a system of nearby open magnetic field lines. Our results suggest that intermittent particle acceleration, likely due to 'bursty' magnetic reconnection, is responsible for the QPPs. The precipitating electrons accelerated towards the chromosphere produce the X-ray and EUV pulsations, while the escaping electrons result in low frequency radio pulses in the form of type III radio bursts. The modulation of the reconnection process, resulting in episodic particle acceleration, explains the presence of these QPPs across the entire spatial range of flaring emission.

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Cited by in corpus (15)

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• Detection of flare multi-periodic pulsations in mid-ultraviolet Balmer continuum, Ly-alpha, hard X-ray, and radio emissions simultaneously
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• First detection of transverse vertical oscillation during the expansion of coronal loops
• Microwave Imaging of Quasi-periodic Pulsations at Flare Current Sheet
• Oscillatory Reconnection of a 2D X-point in a hot coronal plasma
• Detections of Multi-Periodic Oscillations during a Circular Ribbon Flare
• Quasi-periodic Accelerations of Energetic Particles during a Solar Flare
• Oscillatory reconnection as a plasma diagnostic in the solar corona
• Localizing quasi-periodic pulsations in hard X-ray, microwave and Lya emissions of an X6.4 Flare
• Localizing short-period pulsations in hard X-rays and Gamma-rays during an X9.0 flare
• Multiple Regions of Nonthermal Quasi-Periodic Pulsations during the Impulsive Phase of a Solar Flare
• Prevalence of non-stationarity in quasi-periodic pulsations (QPPs) associated with M- and X-class solar flares
• Detecting fast-variation pulsations in solar hard X-ray and radio emissions
• The independence of oscillatory reconnection periodicity from the initial pulse