2015/08/31 by Carolina Robustini, J. Leenaarts, Jorrit Leenaarts +4 · 65 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Emission spectrum #H-alpha #Jet (fluid) #Magnetic field #Magnetic reconnection #Mechanics #Observatory #Physics #Solar and Space Plasma Dynamics #Solar flare #Solar observatory #Solar telescope #Spectral line #Stellar, planetary, and galactic studies #Sunspot #Telescope #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201528022
published in Astronomy and Astrophysics 590, A57 (EDP Sciences) · Accepted for publication in A&A
arxiv created 2016/04/04 · openalex publication_date 2016/04/15 · arxiv updated 2016/05/11 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα line. We study the origin, dynamics, and thermal properties of the jets using high-resolution imaging spectroscopy in Hα from the Swedish 1m Solar Telescope and data from the Solar Dynamics Observatory and Hinode. The Hα jets have lengths of 7–38 Mm, are impulsively accelerated to a speed of ~100 km s-1 close to photospheric footpoints in the LB, and exhibit a constant deceleration consistent with solar effective gravity. They are predominantly launched from one edge of the light bridge, and their footpoints appear bright in the Hα wings. Atmospheric Imaging Assembly data indicates elongated brightenings that are nearly co-spatial with the Hα jets. We interpret them as jets of transition region temperatures. The magnetic field in the light bridge has a strength of 0.8−2 kG and it is nearly horizontal. All jet properties are consistent with magnetic reconnection as the driver.