Excitation of an outflow from the lower solar atmosphere and a co-temporal EUV transient brightening^⋆

¹ Armagh Observatory, College Hill, Armagh BT61 9DG, UK
e-mail: c.j.nelson@shef.ac.uk
² School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK

Received: 30 July 2013
Accepted: 30 October 2013

Abstract

Aims. We analyse an absorption event within the Hα line wings, which has been identified as a surge, and the co-spatial evolution of an EUV brightening, with spatial and temporal scales analogous to a small blinker.

Methods. We conduct a multi-wavelength, multi-instrument analysis using high-cadence, high-resolution data, collected by the Interferometric BIdimensional Spectrometer on the Dunn Solar Telescope, as well as the space-borne Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager instruments on board the Solar Dynamics Observatory.

Results. One large absorption event situated within the plage region trailing the lead sunspot of AR 11579 is identified within the Hα line wings. This event is found to be co-spatially linked to a medium-scale (around 4′′ in diameter) brightening within the transition region and corona. This ejection appears to have a parabolic evolution, first forming in the Hα blue wing before fading and reappearing in the Hα red wing, and comprises a number of smaller fibril events. The line-of-sight photospheric magnetic field shows no evidence of cancellation leading to this event.

Conclusions. Our research has identified clear evidence that at least a subset of transient brightening events in the transition region is linked to the influx of cooler plasma from the lower solar atmosphere during large eruptive events, such as surges. These observations agree with previous numerical researches on the nature of blinkers and, therefore, suggest that magnetic reconnection is the driver of the analysed surge events; however, further research is required to confirm this.