Observations of Condensations at Coronal Hole Boundaries: Dynamics and Implications
Abstract
Two of the outstanding challenges in Heliophysics are determining the mechanism responsible for heating the corona and determining the origin of the slow solar wind. Physical insight and critical constraints on these problems can be obtained by observing the structure and dynamics of coronal plasma, especially the plasma near the boundary between open and closed magnetic flux. We present recent observations from SDO AIA and IRIS of coronal rain in small null-point topologies that frequently result from decayed active regions near coronal hole boundaries. Coronal rain is the intriguing phenomenon in which plasma at coronal temperatures undergoes rapid cooling (from roughly 106 to 103 K), condenses, and falls to the surface. Its origins are not thoroughly understood, but proposed theories posit mechanisms of either temporal or spatial variations in coronal heating. Consequently, our quantitative measurements of coronal rain dynamics place important constraints on the properties of coronal heating. Furthermore, our observations clearly show condensation formation at the open-closed boundary, where interchange reconnection is widely believed to release the slow solar wind. Since these null-point topologies are common features in and near coronal holes, they are ideal targets for the increased temporal and spatial resolution of upcoming solar missions. We will present models for how these condensations form via interchange reconnection and thermal nonequilibrium, and make predictions as to the signatures that Parker Solar Probe and Solar Orbiter will be able to detect.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSH51E2877M
- Keywords:
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- 2164 Solar wind plasma;
- INTERPLANETARY PHYSICSDE: 2169 Solar wind sources;
- INTERPLANETARY PHYSICSDE: 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7524 Magnetic fields;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY