Internal activities in a solar filament and heating to its threads

TL;DR

This study uses multiwavelength solar observations to analyze filament activation, revealing internal magnetic reconnections that heat filament threads and facilitate energy transfer to the solar corona.

Contribution

It provides new insights into the internal magnetic reconnection processes in solar filaments and their role in heating and energy transfer.

Findings

Localized brightenings caused by internal reconnections.

Filament expansion and formation of hot arcades.

Estimated energy of brightenings around 10^{25}-10^{27} erg.

Abstract

Filaments are one of the most common features in the solar atmosphere, and are of significance in solar, stellar and laboratory plasma physics. Using data from the Chinese H$\alpha$ Solar Explorer, the Solar Upper Transition Region Imager and the Solar Dynamics Observatory, we report on multiwavelength imaging and spectral observations of the activation of a small filament. The filament activation produces several localized dynamic brightenings, which are probably produced by internal reconnections of the braided magnetic fields in the filament. The filament expands during the activation and its threads reconnect with the ambient magnetic fields, which leads to the formation of hot arcades or loops overlying the filament. The thermal energy of each of these localized brightenings is estimated in the order of $10^{25}-10^{27} erg$ and the total energy is estimated to be $\sim1.77 \times 10^{28} erg$. Our observations demonstrate that the internal magnetic reconnections in the filament can lead to localized heating to the filament threads and prompt external reconnections with ambient corona structures, and thus could contribute to the energy and mass transferring into the corona.