Authors: Karin Dissauer (NorthWest Research Associates), Graham Barnes (NorthWest Research Associates), KD Leka (NorthWest Research Associates; Institute for Space-Earth Environmental Research, Nagoya University), Stuart Gilchrist (NorthWest Research Associates)

From an observational point of view, small-scale transient activity that occurs in the hours prior
to the onset of the impulsive phase of an eruption could contain essential information on the formation
of pre-eruption configurations as well as on its initiation mechanisms. Such “precursor” activity includes
for example transient brightenings in EUV and X-rays that may result from small-scale reconnection and
plasma heating or coronal dimming signatures that may indicate early filament activation or the rise of overlying
field enabling a Coronal Mass Ejection (CME) to subsequently occur. In this contribution we ask the question
if information on the occurrence of pre-eruption dimmings and brightenings, their timings with respect to each
other, their locations and the time evolution of basic parameters characterizing them could be used to shed light
on the underlying physical mechanisms of solar eruptions.
We analyze both phenomena in concert using archive data from the Atmospheric Imaging Assembly (AIA) and the
Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) over an interval of two hours before selected flare/CME events and check if they occur at strategically favorable locations related to the topology of the magnetic configuration of a PFSS model. The realization of the coronal magnetic field is compared to more sophisticated NLFFF extrapolations for the existence and locations of topological structures.

This material is based upon work supported by NASA under award No. 80NSSC21K0738 and the NSF under AGS-ST Grant 2154653.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Aeronautics and Space Administration or the National Science Foundation.