Physics Department News

Energy releases, such as solar flares, trigger waves and oscillations in the upper part of the solar atmosphere, the corona. The study of these waves and oscillations allows comparisons to magnetohydrodynamic theory and modelling to be made, and seismological inversions based on this comparison. Simultaneous EUV imaging with satellites and radio observations with ground-based telescopes make it possible to study how these waves and oscillations can produce or modify radio emission from the coronal plasma.

We analysed an individual flaring event, the subsequent coronal mass ejection (CME) and wave activity and the associated type II radio burst. We find evidence that a series of quasi-periodic ‘sparks’ in the radio spectra are linked to disturbances seen in the low corona in the EUV band. This is the first observation which links quasi-periodic fast waves observed in the EUV band to quasi-periodic features in the radio spectra. This is a promising development in the study of these periodic waves, and may lead to an increased number of detections, and the development of seismology based on them.

• Caption to figures: Figure 1. a) : Solar radio spectrum in the range 25-170 MHz. Four regions of enhanced emission (the quasi-periodic 'sparks') are indicated by R1-R4. b): A running-difference snapshot from the EUV images of one of the periodic fast waves, the vertical blue lines indicate the position of the wave front.
• Publication: C. R. Goddard, G. Nistico, V. M. Nakariakov, I. V. Zimovets, and S.M. White, 2016A&A...594A..96G
• DOI: 2016A&A...594A..96G