H β Spicules, Small-scale Jets, and H β Microflashes: Subarcsecond Dynamic Events and Their Magnetic Origins in the Lower Solar Chromosphere Observed by DKIST

Abstract We examine an on-disk solar quiet region of enhanced magnetic network using H β images from Daniel K. Inouye Solar Telescope’s (DKIST’s) Visible Broadband Imager (VBI) and line-of-sight magnetograms from DKIST’s Visible Spectro-Polarimeter (ViSP). We also compare the ViSP magnetograms with coaligned cotemporal line-of-sight magnetograms from the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI). We find (i) two types of chromospheric jet-like features: H β spicules and small-scale jets. Both are rooted near edges of magnetic network lanes. Several sit close to ViSP-detected tiny islands of either minority-polarity flux or dips in majority-polarity flux; hence, they plausibly stem from mixed-polarity magnetic flux and are caused by chromospheric magnetic reconnection. For H β spicules, the average width, length, lifetimes, and speeds are 420 ± 400 km, 2600 ± 1600 km, 4.3 ± 0.25 minutes, and 12 ± 4.7 km s −1 . For small-scale jets, they are 385 ± 100 km, 620 ± 40 km, 5 ± 3 minutes, and 4.4 ± 1.5 km s −1 . (ii) H β microflashes sit in evidently unipolar flux. Their widths, lengths, lifetimes, and speeds are 180 ± 65 km, 365 ± 100 km, 4.3 ± 2.6 minutes, and 3.1 ± 0.2 km s −1 . (iii) At the base of a coronal plume, due to its higher spatial resolution than HMI, ViSP shows both some very strong (>800 G) majority-polarity flux not shown by HMI and some subarcsecond minority-polarity flux inclusions not shown by HMI. These subarcsecond chromospheric transients carry sufficient energy (≃10 24 erg) to transiently heat the local chromosphere and corona and potentially contribute to solar wind acceleration. They may represent the small-scale end of a continuum of magnetic-reconnection-driven activity, highlighting the importance of DKIST’s high-resolution magnetic field measurements for understanding small-scale chromospheric dynamics.