Related papers: Fine structures in the atmosphere above a sunspot …
Aims: The aim of this paper is to demonstrate that millimeter wave data can be used to distinguish between various atmospheric models of sunspots, whose temperature structure in the upper photosphere and chromosphere has been the source of…
Recurrent chromospheric fan-shaped jets highlight the highly dynamic nature of the solar atmosphere. They have been named as ''light walls'' or ''peacock jets'' in high-resolution observations. In this study, we examined the underlying…
Small-scale jet-like eruptions, such as picoflare jets and jetlets, are recognized as potential contributors to coronal heating and solar wind acceleration, yet their physical origin is still not fully established. Using…
A variety of periodic phenomena have been observed in conjunction with large solar jets. We aim to find further evidence for {(quasi-)}periodic behaviour in solar jets and determine what the periodic behaviour can tell us about the…
Sunspots contain multiple small-scale structures in the umbra and in the penumbra. Despite extensive research on this subject in pre-Hinode era multiple questions concerning fine-scale structures of sunspots, their formation, evolution and…
We present high spatial and high temporal resolution observations of the quiet Sun in H-alpha obtained with the Swedish 1-m Solar Telescope on La Palma. We observe that many mottles, jet-like features in the quiet Sun, display clear up- and…
A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hours by the EUV Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8-10.…
We present data of 10 penumbral microjets (PMJs) observed in H\alpha, Ca II 8542 \AA, and Fe I 6302 \AA line pair with the Swedish 1 m Solar Telescope (SST) with CRISP and Ca II K with SST/CHROMIS in active region NOAA 12599 on the 12th…
The various mechanisms of magneto-convective energy transport determines the structure of sunspots and active regions. We characterise the appearance of light bridges and other fine-structure details and elaborate on their…
We present conspicuous activities of plasma ejections along a light bridge of a stable and mature sunspot in NOAA 8971 on 2000 May 02. We found the ejections both in the H-alpha (10^4 K) images obtained with the Domeless Solar Telescope…
Oscillations in sunspot umbrae exhibit remarkable differences between the photosphere and chromosphere. We evaluate two competing scenarios proposed for explaining those observations: a chromospheric resonant cavity and waves traveling from…
The physics of Sunspots is a fascinating and demanding field of research in solar astronomy. Interaction of magnetic fields and plasma flows takes place in a tangled magnetic geometry and occurs on spatial scales that pose a continuous…
We report the simultaneous presence of chromospheric umbral flashes and associated umbral waves, and propagating coronal disturbances, in a sunspot and related active region. We have analyzed time-distance maps obtained using the…
The commonly observed jets provide critical information on the small-scale energy release in the solar atmosphere. We report a near disk-center jet on 2010 July 20, observed by the Solar Dynamics Observatory. In this event, the standard…
In the solar atmosphere, the acoustic cutoff frequency is a local quantity which depends on the atmospheric height. It separates the low-frequency evanescent waves from the high-frequency propagating waves. We measure the cutoff frequency…
Penumbrae are known to be area of mainly horizontal magnetic field surrounding umbrae of relatively large and mature sunspots. In this paper, we observationally studied the formation of penumbrae in NOAA10978, where several penumbral…
Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the…
Flare ribbons serve as chromospheric footprints of energy deposition resulting from particle acceleration during magnetic reconnection. Their fine-scale structure provides a valuable tool for probing the dynamics of the flare reconnection…
We present a study of wave processes in the sunspot region NOAA 12670 on 2017 August 10 observed by the Goode Solar Telescope in the TiO 7057 A and Ha 6563 A spectral lines. To study the distribution of power oscillations and their…
Macrospicules are typically described as solar jets that are larger and longer-lived than spicules, and visible mostly in transition-region spectral lines. They show a broad variation in properties, which pose substantial difficulties for…