Formation of coronal rain triggered by impulsive heating associated with magnetic reconnection

Abstract

Coronal rain consists of cool plasma condensations formed in coronal loops as a result of thermal instability. The standard models of coronal rain formation assume that the heating is quasi-steady and localised at the coronal loop footpoints. We present an observation of magnetic reconnection in the corona and the associated impulsive heating triggering formation of coronal rain condensations. We analyse combined SDO/AIA and IRIS observations of a coronal rain event following a reconnection between threads of a low-lying prominence flux rope and surrounding coronal field lines. The reconnection of the twisted flux rope and open field lines leads to a release of magnetic twist. Evolution of the emission of one of the coronal loops involved in the reconnection process in different AIA bandpasses suggests that the loop becomes thermally unstable and is subject to the formation of coronal rain condensations following the reconnection and that the associated heating is localised in the upper part of the loop leg. We conclude that in addition to the standard models of thermally unstable coronal loops with heating localised exclusively in the footpoints, thermal instability and subsequent formation of condensations can be triggered by the impulsive heating associated with magnetic reconnection occurring anywhere along a magnetic field line.

9 pages, 6 figures, accepted by A&A

References in corpus (9)

• Small-scale filament eruptions as the driver of solar coronal hole X-ray jets
• Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption
• Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare
• The multi-thermal and multi-stranded nature of coronal rain
• Detection of supersonic downflows and associated heating events in the transition region above sunspots
• Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event
• Coronal rain in magnetic arcades: Rebound shocks, Limit cycles, and Shear flows
• Reconnection-Condensation Model for Solar Prominence Formation
• Observing the formation of flare-driven coronal rain

Cited by in corpus (12)

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• Self-consistent 3D radiative MHD simulations of coronal rain formation and evolution
• Electron Beams Cannot Directly Produce Coronal Rain
• Coronal Condensation as the Source of Transition Region Supersonic Downflows above a Sunspot
• Relation of coronal rain originating from coronal condensations to interchange magnetic reconnection
• On-disk solar coronal condensations facilitated by magnetic reconnection between open and closed magnetic structures
• From Chromospheric Evaporation to Coronal Rain: An Investigation of the Mass and Energy Cycle of a Flare
• Revisiting the formation mechanism for coronal rain from previous studies
• Coronal rain formation in a two-fluid approximation
• A new view of the solar interface region from the Interface Region Imaging Spectrograph (IRIS)