Ellerman bombs and UV bursts: reconnection at different atmospheric layers?

by Ada Ortiz

Hosted by Rosseland Centre for Solar Physics, University of Oslo on November 29, 2018

Abstract

The emergence of magnetic flux through the photosphere and into the outer solar atmosphere produces, amongst many other phenomena, the appearance of Ellerman bombs (EBs) in the photosphere. EBs are observed in the wings of Hα and are highly likely to be due to reconnection in the photosphere, below the chromospheric canopy. But signs of the reconnection process are also observed in several other spectral lines, typical of the chromosphere or transition region. An example are the UV bursts observed in the transition region lines of Si IV. In this work we analyse high-cadence coordinated observations between the Swedish 1-m Solar Telescope (SST) and the IRIS spacecraft in order to study the possible relationship between reconnection events at different layers in the atmosphere, and in particular, the timing history between them. High-cadence, high-resolution Hα images from the SST provide us with the positions, timings and trajectories of Ellerman bombs in an emerging flux region. Simultaneous co-aligned IRIS slit-jaw images at 2796Å, 1400Å and 1330Å and detailed Mg II and Si IV spectra from the fast spectrograph raster allow us to study the possible chromospheric/transition region counterparts of those photospheric Ellerman bombs. Our main goal is to study whether there is a temporal and spatial relationship between the appearance of an EB and the appearance of a UV burst.