Penumbral Waves driving Solar chromospheric fan-shaped jets

TL;DR

This study uses high-resolution solar observations to link penumbral waves with the generation of fan-shaped chromospheric jets, revealing their dynamics, recurrent nature, and associated hot plasma signatures.

Contribution

It provides new evidence that penumbral waves drive fan-shaped jets at the solar limb, highlighting the role of recurrent reconnection and wave activity in jet formation.

Findings

Jets have upward velocities of 30 km/s and extend up to 8 Mm.

Jet occurrence is periodic, matching sunspot penumbral wave periods.

Jets show signatures of very hot plasma at their fronts.

Abstract

We use H$\alpha$ imaging spectroscopy taken via the Swedish 1-m Solar Telescope (SST) to investigate the occurrence of fan-shaped jets at the solar limb. We show evidence for near-simultaneous photospheric reconnection at a sunspot edge leading to the jets appearance, with upward velocities of 30\ks, and extensions up to 8~Mm. The brightening at the base of the jets appears recurrent, with a periodicity matching that of the nearby sunspot penumbra, implying running penumbral waves could be the driver of the jets. The jets' constant extension velocity implies that a driver counteracting solar gravity exists, possibly as a result of the recurrent reconnection erupting material into the chromosphere. These jets also show signatures in higher temperature lines captured from the Solar Dynamics Observatory (SDO), indicating a very hot jet front, leaving behind optically thick cool plasma in its wake.