Various Activities above Sunspot Light Bridges in IRIS Observations: Classification and Comparison
arXiv:2202.10159 · doi:10.3847/1538-4357/ac5912
Abstract
Light bridges (LBs) are among the most striking sub-structures in sunspots, where various activities have been revealed by recent high-resolution observations from the Interface Region Imaging Spectrograph (IRIS). According to the variety of physical properties, we classified these activities into four distinct categories: transient brightening (TB), intermittent jet (IJ), type-I light wall (LW-I), and type-II light wall (LW-II). In IRIS 1400/1330 Å observations, TBs are characterized by abrupt emission enhancements, and IJs appear as collimated plasma ejections with a width of 1-2 Mm at some LB sites. Most observed TBs are associated with IJs and show superpositions of some chromosphere absorption lines on enhanced and broadened wings of C II and Si IV lines, which could be driven by intermittent magnetic reconnection in the lower atmosphere. LW-I and LW-II are wall-shaped structures with bright fronts above the whole LB. An LW-I has a continuous oscillating front with a typical height of several Mm and an almost stationary period of 4-5 minutes. On the contrary, an LW-II has a indented front with a height of over 10 Mm, which has no stable period and is accompanied by recurrent TBs in the entire LB. These results support that LW-IIs are driven by frequent reconnection occurring along the whole LB due to large-scale magnetic flux emergence or intrusion, rather than the leakage of waves producing LW-Is. Our observations reveal a highly dynamical scenario of activities above LBs driven by different basic physical processes, including magneto-convection, magnetic reconnection, and wave leakage.
23 pages, 11 figures, 2 tables, accepted for publication in ApJ
References in corpus (24)
- The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches
- Hot Explosions in the Cool Atmosphere of the Sun
- Vigorous convection in a sunspot granular light bridge
- Explosive events on sub-arcsecond scale in IRIS observations: a case study
- Super-strong Magnetic Field in Sunspots
- Three-dimensional structure of a sunspot light bridge
- Small-scale chromospheric jets above a sunspot light bridge
- Oscillating light wall above a sunspot light bridge
- Various Local Heating Events in the Earliest Phase of Flux Emergence
- Coronal microjets in quiet-Sun regions observed with the Extreme Ultraviolet Imager onboard Solar Orbiter
- Surge-like oscillations above sunspot light bridges driven by magnetoacoustic shocks
- Spontaneous Generation of delta-sunspots in Convective Magnetohydrodynamic Simulation of Magnetic Flux Emergence
- Investigating the Transition Region Explosive Events and Their Relationship to Network Jets
- Active region fine structure observed at 0.08 arcsec resolution
- Abnormal oscillation modes in a waning light bridge
- Enhancement of a sunspot light wall with external disturbances
- Heating of the solar chromosphere in a sunspot light bridge by electric currents
- A solar flare disturbing a light wall above a sunspot light bridge
- Heating at the remote footpoints as a brake on jet flows along loops in the solar atmosphere
- Sunspot Light Walls Suppressed by Nearby Brightenings
- Sunspot penumbral filaments intruding into a light bridge and the resultant reconnection jets
- Signatures of the impact of flare ejected plasma on the photosphere of a sunspot light-bridge
- Structure of sunspot light bridges in the chromosphere and transition region
- Small-scale Bright Blobs Ejected from a Sunspot Light Bridge