Filament Channels: Isolated Laboratories of Plasma Heating in the Solar Corona

Abstract:

Solar filament channels are complex systems comprising photospheric, chromospheric and coronal components. These components include magnetic neutral lines, supergranule cells, fibrils (spicules), filaments (prominences when observed on the limb), coronal cells, filament cavities and their overlying coronal arcades. Filaments are very highly structured and extend in height from the photosphere to the corona. Filament cores have chromospheric temperatures - 10,000 K (even at coronal heights ~ 100 Mm), surrounded by hotter plasma with temperature up to ~50,000 K. The whole filament is isolated from the rest of the solar corona by an envelope - the filament channel cavity - with temperatures of about 2,000,000 K. The filament channel cavity is even hotter than the solar corona outside the filament channel arcade.

The compactness and big temperature variations make filament channels unique ready-to-go laboratories of coronal plasma heating and thermodynamics. In this work we discuss possible sources and mechanisms of heating in the filament channel environment. In particular, we address the mechanisms of magnetic canceling and current sheet dissipation.