“Signatures of Localised Magnetic Reconnection in the Photosphere and Corona”

by Chris J. Nelson, Queen’s University Belfast / University of Sheffield (UK)

Abstract: Magnetic reconnection has been shown to take place throughout the solar atmosphere, from small-scale events in the photosphere to large-scale events in the corona. The first half of this talk provides an overview of our current understanding of UV bursts, small-scale (spatial extents of around 725 km) and short-lived (lifetimes less than 1 minute) brightenings (e.g., Ellerman bombs, Quiet-Sun Ellerman-like Brightenings, IRIS bursts) which are observed in the solar photosphere, often using high-resolution data from the Swedish Solar Telescope and Interface Region Imaging Spectrometer. We detail the evidence that supports the hypothesis that these events occur as a response to magnetic reconnection in the lower solar atmosphere and outline some open questions for future research. In the second half of the talk, we will present some recent results which provide evidence of heating in a non-flaring Active Region caused by the on-set of the non-linear phase of the internal Kink Instability. The Kink Instability causes run-away displacements to the axis of twisted bundles of magnetic field lines. For the internal Kink Instability, as the twisted field lines are displaced, currents build up along their length, thereby facilitating the occurrence of magnetic reconnection. This reconnection converts a proportion of the free magnetic energy in the system to thermal energy leading to heating in the local plasma to temperatures over 10 MK.

Dimarts 8 de maig de 2018, a les 12 h
Sala de Seminaris, 3r pis Dpt. Física
Edifici Mateu Orfila , UIB

Organitza: Grup de Física Solar i IAC3