Bright Dots and Coronal Plume Formation in Sunspot Penumbra

Abstract

Coronal plumes are narrow, collimated structures that are primarily viewed above the solar poles and in coronal holes in the extreme ultraviolet, but also in sunspots. Open questions remain about plume formation, including the role of small-scale transients and whether plumes embedded in different magnetic field configurations have similar formation mechanisms. We report on coordinated Solar Orbiter/Extreme Ultraviolet Imager (EUI), Interface Region Imaging Spectrograph, and Solar Dynamics Observatory observations of the formation of a plume in sunspot penumbra in 2022 March. During this observation, Solar Orbiter was positioned near the Earth-Sun line and EUI observed at a 5 s cadence with a spatial scale of 185 km pixel${}^{-1}$ in the solar corona. We observe fine-scale dots at various locations in the sunspot, but the brightest and highest density of dots is at the plume base. Space-time maps along the plume axis show parabolic and V-shaped patterns, and we conclude that some of these dots are possible signatures of magneto-acoustic shocks. Compared to other radial cuts around the sunspot, along the plume shows the longest periods (~7 minutes) and the most distinct tracks. Bright dots at the plume base are mostly circular and do not show elongations from a fixed origin, in contrast to jetlets and previously reported penumbral dots. We do not find high-speed, repeated downflows along the plume, and the plume appears to brighten coherently along its length. Our analysis suggests that jetlets and downflows are not a necessary component of this plume's formation, and that mechanisms for plume formation could be dependent on magnetic topology and the chromospheric wave field.

16 pages, 10 figures

References in corpus (24)

• The Solar Orbiter mission -- Science overview
• Dynamic Fibrils are driven by Magnetoacoustic Shocks
• High Resolution Observations and Modeling of Dynamic Fibrils
• On the generation of solar spicules and Alfvénic waves
• First direct measurements of transverse waves in solar polar plumes using SDO/AIA
• Observations of Subarcsecond Bright Dots in the Transition Region above Sunspots with the Interface Region Imaging Spectrograph
• Detection of supersonic downflows and associated heating events in the transition region above sunspots
• STEREO Observations of Quasi-Periodically Driven High Velocity Outflows in Polar Plumes
• Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes
• Fine-scale explosive energy release at sites of prospective magnetic flux cancellation in the core of the solar active region observed by Hi-C 2.1, IRIS and SDO
• Quasiperiodic Energy Release and Jets at the Base of Solar Coronal Plumes
• Observations and numerical models of solar coronal heating associated with spicules
• Plumelets: Dynamic Filamentary Structures in Solar Coronal Plumes
• Coronal Condensation as the Source of Transition Region Supersonic Downflows above a Sunspot
• Lateral downflows in sunspot penumbral filaments and their temporal evolution
• Dynamics of subarcsecond bright dots in the transition region above sunspot and their relation to penumbral micro-jets
• Multi-wavelength Study of Transition Region Penumbral Subarcsecond Bright Dots Using IRIS and NST
• On-disk solar coronal condensations facilitated by magnetic reconnection between open and closed magnetic structures
• Signatures of dynamic fibrils at the coronal base: Observations from Solar Orbiter/EUI
• Modelling the connection between propagating disturbances and solar spicules
• Evolution of dynamic fibrils from the cooler chromosphere to the hotter corona
• A multi-diagnostic spectral analysis of penumbral microjets
• Prospective Implications of EUV Coronal Plumes for Magnetic-network Genesis of Coronal Heating, Coronal-hole Solar Wind, and Solar-wind Magnetic-field Switchbacks
• Thermodynamic Evolution of Plumes