Plumelets: Dynamic Filamentary Structures in Solar Plumes
Abstract
Solar plumes long seemed to possess a simple geometry supporting spatially coherent, stable outflow without significant fine structure. Recent high-resolution observations have challenged this picture by revealing numerous transient, small-scale, collimated outflows ("jetlets") at the base of plumes (see Kumar et al. presentation in this session). The dynamic filamentary structure of solar plumes above these outflows, and its relationship with the overall plume structure, have remained largely unexplored. We report a statistical analysis of continuously observed fine structure inside a bright plume within a mid-latitude coronal hole during 2016 July 2-3. By applying advanced edge-enhancement and spatiotemporal analysis techniques to extended series of highresolution images from the Solar Dynamics Observatory's Atmospheric Imaging Assembly, we determined that the plume was composed of numerous time-evolving bright filamentary substructures, referred to as "plumelets" in this paper, that accounted for most of the plume emission. The number of simultaneously identifiable plumelets varied over the observation period, was positively correlated with plume brightness, and peaked in the fully formed plume. The plumelets had transverse widths of 10 Mm and intermittently supported upwardly propagating periodic disturbances with phase speeds of 190-260 km s-1 and longitudinal wavelengths of 55-65 Mm. The characteristic frequency (3.5 mHz) is commensurate with that of solar p-modes. Oscillations in neighboring plumelets are uncorrelated, indicating that the waves could be driven by p-mode flows at spatial scales smaller than the plumelet separation. Multiple independent sources of outflow within a single coronal plume should impart significant fine structure to the fast solar wind and be detectable by Parker Solar Probe at perihelion.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSH0240003K
- Keywords:
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- 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7514 Energetic particles;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7519 Flares;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7526 Magnetic reconnection;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY