Location of Decimetric Pulsations in Solar Flares

Abstract

This work investigates the spatial relation between coronal X-ray sources and coherent radio emissions, both generally thought to be signatures of particle acceleration. Two limb events were selected during which the radio emission was well correlated in time with hard X-rays. The radio emissions were of the type of decimetric pulsations as determined from the spectrogram observed by Phoenix-2 of ETH Zurich. The radio positions were measured from observations with the Nancay Radioheliograph between 236 and 432 MHz and compared to the position of the coronal X-ray source imaged with RHESSI. The radio pulsations originated at least 30 - 240 Mm above the coronal hard X-ray source. The altitude of the radio emission increases generally with lower frequency. The average positions at different frequencies are on a line pointing approximately to the coronal hard X-ray source. Thus, the pulsations cannot be caused by electrons trapped in the flare loops, but are consistent with emission from a current sheet above the coronal source.

Solar Physics, in press

References in corpus (3)

• Relations between concurrent hard X-ray sources in solar flares
• Microwave Quasi-periodic Pulsations in Multi-timescales Associated with a Solar Flare/CME Event
• Broadband Quasi-Periodic Radio and X-ray Pulsations in a Solar Flare

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• Fast magnetoacoustic waves in a fan structure above the coronal magnetic null point
• Common origin of quasi-periodic pulsations in microwave and decimetric solar radio bursts
• Multiple electron acceleration instances during a series of solar microflares observed simultaneously at X-rays and microwaves
• Observation of a Large-scale Quasi-circular Secondary Ribbon associated with Successive Flares and a Halo CME
• CME development in the corona and interplanetary medium: A multi-wavelength approach
• Power-law Indices of EUV Intensity Power Spectrum in Flaring Coronal Active Regions