A multi-diagnostic spectral analysis of penumbral microjets

Drews, Ainar; Voort, L. Rouppe van der

doi:10.1051/0004-6361/202037911

Cited by 7 publications

(7 citation statements)

References 35 publications

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“…Furthermore, clear PMJ detections are mostly found in the inner penumbra, where we find fewer PEBs as compared to the outer penumbra. Recently, Buehler et al (2019) and Drews & Rouppe van der Voort (2020) connected Ca ii 8542 Å PMJs with dark fibrilar structures close to the line core in Hα. The connection between PEBs and PMJs warrants further study and requires simultaneous observations of multiple spectral lines and extreme high temporal evolution to resolve the onset of PMJs (Rouppe van der Voort & Drews 2019).…”

Section: Discussionmentioning

confidence: 99%

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Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

Voort

Joshi

Henriques

et al. 2021

A&A

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Context. Ellerman bombs are regions with enhanced Balmer line wing emission and mark magnetic reconnection in the deep solar atmosphere in active regions and the quiet Sun. They are often found in regions where opposite magnetic polarities are in close proximity. Recent high-resolution observations suggest that Ellerman bombs are more prevalent than previously thought. Aims. We aim to determine the occurrence of Ellerman bombs in the penumbra of sunspots. Methods. We analyzed high spatial resolution observations of sunspots in the Balmer Hα and Hβ lines as well as auxiliary continuum channels obtained with the Swedish 1-m Solar Telescope and applied the k-means clustering technique to systematically detect and characterize Ellerman Bombs. Results. Features with all the defining characteristics of Ellerman bombs are found in large numbers over the entire penumbra. The true prevalence of these events is only fully appreciated in the Hβ line due to the highest spatial resolution and lower chromospheric opacity. We find that the penumbra hosts some of the highest Ellerman bomb densities, surpassed only by the moat in the immediate surroundings of the sunspot. Some penumbral Ellerman bombs show flame morphology and rapid dynamical evolution. Many penumbral Ellerman bombs are fast moving with typical speed of 3.7 km s−1 and sometimes more than 10 km s−1. Many penumbral Ellerman bombs migrate from the inner to the outer penumbra over hundreds of km, and some continue moving beyond the outer penumbral boundary into the moat. Many penumbral Ellerman bombs are found in the vicinity of regions with opposite magnetic polarity. Conclusions. We conclude that reconnection is a near continuous process in the low atmosphere of the penumbra of sunspots that manifest in the form of penumbral Ellerman bombs. These are so prevalent that they may be a major sink of sunspot magnetic energy.

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Section: Discussionmentioning

confidence: 99%

“…The Ca ii 8542 Å spectra were not included in our analysis. This data were earlier analyzed by Drews & Rouppe van der Voort (2020) to study penumbral micro jets, and the co-aligned SST and IRIS data were publicly released as described by Rouppe van der .…”

Section: Observationsmentioning

confidence: 99%

Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

Voort

Joshi

Henriques

et al. 2021

A&A

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show abstract

“…Since the follow-up studies have not identified any significant Doppler velocities within these structures (see e.g. Reardon et al 2013;Drews & Rouppe van der Voort 2017;Esteban Pozuelo et al 2019;Drews & Rouppe van der Voort 2020), the second scenario is now favoured. However, the propagation of these events is still not evident due to the lack of knowledge of the magnetic field at atmospheric layers above the photosphere.…”

Section: Large-scale Magnetic Structuresmentioning

confidence: 99%

The European Solar Telescope

Noda

Schlichenmaier

Rubio

et al. 2022

A&A

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The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems.

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“…The Ca ii 8542 Å spectra were not included in our analysis. This data was earlier analyzed by Drews & Rouppe van der Voort (2020) to study penumbral micro jets and the co-aligned SST and IRIS data were publicly released as described by Rouppe van der .…”

Section: Observationsmentioning

confidence: 99%

Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

van der Voort,

Joshi,

Henriques

et al. 2021

Preprint

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Context. Ellerman bombs are regions with enhanced Balmer line wing emission and mark magnetic reconnection in the deep solar atmosphere in active regions and quiet Sun. They are often found in regions where opposite magnetic polarities are in close proximity. Recent high resolution observations suggest that Ellerman bombs are more prevalent than thought before. Aims. We aim to determine the occurrence of Ellerman bombs in the penumbra of sunspots. Methods. We analyze high spatial resolution observations of sunspots in the Balmer Hα and Hβ lines as well as auxiliary continuum channels obtained with the Swedish 1-m Solar Telescope and apply the k-means clustering technique to systematically detect and characterize Ellerman Bombs. Results. Features with all the defining characteristics of Ellerman bombs are found in large numbers over the entire penumbra. The true prevalence of these events is only fully appreciated in the Hβ line due to highest spatial resolution and lower chromospheric opacity. We find that the penumbra hosts some of the highest Ellerman bomb densities, only surpassed by the moat in the immediate surroundings of the sunspot. Some penumbral Ellerman bombs show flame morphology and rapid dynamical evolution. Many penumbral Ellerman bombs are fast moving with typical speed of 3.7 km s −1 and sometimes more than 10 km s −1 . Many penumbral Ellerman bombs migrate from the inner to the outer penumbra over hundreds of km and some continue moving beyond the outer penumbral boundary into the moat. Many penumbral Ellerman bombs are found in the vicinity of regions with opposite magnetic polarity. Conclusions. We conclude that reconnection is a near continuous process in the low atmosphere of the penumbra of sunspots as manifest in the form of penumbral Ellerman bombs. These are so prevalent that they may be a major sink of sunspot magnetic energy.

show abstract

A multi-diagnostic spectral analysis of penumbral microjets

Cited by 7 publications

References 35 publications

Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

The European Solar Telescope

Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae

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