Author name code: barczynski ADS astronomy entries on 2022-09-14 author:Barczynski, Krzystof ------------------------------------------------------------------------ Title: Spatial distribution of jets in solar active regions Authors: Odermatt, J.; Barczynski, K.; Harra, L. K.; Schwanitz, C.; Krucker, S. Bibcode: 2022A&A...665A..29O Altcode: 2022arXiv220709923O Context. Solar active regions are known to have jets. These jets are associated with heating and the release of particles into the solar wind.
Aims: Our aim is to understand the spatial distribution of coronal jets within active regions to understand if there is a preferential location for them to occur.
Methods: We analysed five active regions using Solar Dynamics Observatory Atmospheric Imaging Assembly data over a period of 2-3.5 days when the active regions were close to disk centre. Each active region had a different age, magnetic field strength, and topology. We developed a methodology for determining the position and length of the jets.
Results: Jets are observed more frequently at the edges of the active regions and are more densely located around a strong leading sunspot. The number of coronal jets for our active regions is dependent on the age of the active region. The older active regions produce more jets than younger ones. Jets were observed dominantly at the edges of the active regions, and not as frequently in the centre. The number of jets is independent of the average unsigned magnetic field and total flux density in the whole active region. The jets are located around the edges of the strong leading sunspot. Title: Automatic detection of small-scale EUV brightenings observed by the Solar Orbiter/EUI Authors: Alipour, N.; Safari, H.; Verbeeck, C.; Berghmans, D.; Auchère, F.; Chitta, L. P.; Antolin, P.; Barczynski, K.; Buchlin, É.; Aznar Cuadrado, R.; Dolla, L.; Georgoulis, M. K.; Gissot, S.; Harra, L.; Katsiyannis, A. C.; Long, D. M.; Mandal, S.; Parenti, S.; Podladchikova, O.; Petrova, E.; Soubrié, É.; Schühle, U.; Schwanitz, C.; Teriaca, L.; West, M. J.; Zhukov, A. N. Bibcode: 2022A&A...663A.128A Altcode: 2022arXiv220404027A Context. Accurate detections of frequent small-scale extreme ultraviolet (EUV) brightenings are essential to the investigation of the physical processes heating the corona.
Aims: We detected small-scale brightenings, termed campfires, using their morphological and intensity structures as observed in coronal EUV imaging observations for statistical analysis.
Methods: We applied a method based on Zernike moments and a support vector machine (SVM) classifier to automatically identify and track campfires observed by Solar Orbiter/Extreme Ultraviolet Imager (EUI) and Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA).
Results: This method detected 8678 campfires (with length scales between 400 km and 4000 km) from a sequence of 50 High Resolution EUV telescope (HRIEUV) 174 Å images. From 21 near co-temporal AIA images covering the same field of view as EUI, we found 1131 campfires, 58% of which were also detected in HRIEUV images. In contrast, about 16% of campfires recognized in HRIEUV were detected by AIA. We obtain a campfire birthrate of 2 × 10−16 m−2 s−1. About 40% of campfires show a duration longer than 5 s, having been observed in at least two HRIEUV images. We find that 27% of campfires were found in coronal bright points and the remaining 73% have occurred out of coronal bright points. We detected 23 EUI campfires with a duration greater than 245 s. We found that about 80% of campfires are formed at supergranular boundaries, and the features with the highest total intensities are generated at network junctions and intense H I Lyman-α emission regions observed by EUI/HRILya. The probability distribution functions for the total intensity, peak intensity, and projected area of campfires follow a power law behavior with absolute indices between 2 and 3. This self-similar behavior is a possible signature of self-organization, or even self-organized criticality, in the campfire formation process.

Supplementary material (S1-S3) is available at https://www.aanda.org Title: Stereoscopy of extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI Authors: Zhukov, A. N.; Mierla, M.; Auchère, F.; Gissot, S.; Rodriguez, L.; Soubrié, E.; Thompson, W. T.; Inhester, B.; Nicula, B.; Antolin, P.; Parenti, S.; Buchlin, É.; Barczynski, K.; Verbeeck, C.; Kraaikamp, E.; Smith, P. J.; Stegen, K.; Dolla, L.; Harra, L.; Long, D. M.; Schühle, U.; Podladchikova, O.; Aznar Cuadrado, R.; Teriaca, L.; Haberreiter, M.; Katsiyannis, A. C.; Rochus, P.; Halain, J. -P.; Jacques, L.; Berghmans, D. Bibcode: 2021A&A...656A..35Z Altcode: 2021arXiv210902169Z Context. The three-dimensional fine structure of the solar atmosphere is still not fully understood as most of the available observations are taken from a single vantage point.
Aims: The goal of the paper is to study the three-dimensional distribution of the small-scale brightening events ("campfires") discovered in the extreme-UV quiet Sun by the Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter.
Methods: We used a first commissioning data set acquired by the EUI's High Resolution EUV telescope on 30 May 2020 in the 174 Å passband and we combined it with simultaneous data taken by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory in a similar 171 Å passband. The two-pixel spatial resolution of the two telescopes is 400 km and 880 km, respectively, which is sufficient to identify the campfires in both data sets. The two spacecraft had an angular separation of around 31.5° (essentially in heliographic longitude), which allowed for the three-dimensional reconstruction of the campfire position. These observations represent the first time that stereoscopy was achieved for brightenings at such a small scale. Manual and automatic triangulation methods were used to characterize the campfire data.
Results: The height of the campfires is located between 1000 km and 5000 km above the photosphere and we find a good agreement between the manual and automatic methods. The internal structure of campfires is mostly unresolved by AIA; however, for a particularly large campfire, we were able to triangulate a few pixels, which are all in a narrow range between 2500 and 4500 km.
Conclusions: We conclude that the low height of EUI campfires suggests that they belong to the previously unresolved fine structure of the transition region and low corona of the quiet Sun. They are probably apexes of small-scale dynamic loops heated internally to coronal temperatures. This work demonstrates that high-resolution stereoscopy of structures in the solar atmosphere has become feasible. Title: Stereoscopic measurements of coronal Doppler velocities Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini, C. H.; Auchère, F.; Berghmans, D.; Buchlin, É.; Dolla, L.; Mierla, M.; Parenti, S.; Rodriguez, L. Bibcode: 2021A&A...655A..57P Altcode: 2021arXiv210802280P Context. The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving the ecliptic plane, opens up opportunities for the combined analysis of measurements obtained by solar imagers and spectrometers. For the first time different space spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere.
Aims: The aim of this work is to prepare a methodology to facilitate the reconstruction of 3D vector velocities from two stereoscopic line of sight (LOS) Doppler velocity measurements using the Spectral Imaging of the Coronal Environment (SPICE) on board the Solar Orbiter and the near-Earth spectrometers, while widely separated in space.
Methods: We developed the methodology using the libraries designed earlier for the STEREO mission, but applied to spectroscopic data from the Hinode mission and the Solar Dynamics Observatory. We used well-known methods of static and dynamic solar rotation stereoscopy and the methods of extreme ultraviolet (EUV) stereoscopic triangulation for optically thin coronal EUV plasma emissions. We developed new algorithms using analytical geometry in space to determine the 3D velocity in coronal loops.
Results: We demonstrate our approach with the reconstruction of 3D velocity vectors in plasma flows along `open' and `closed' magnetic loops. This technique will be applied to an actual situation of two spacecraft at different separations with spectrometers on board during the Solar Orbiter nominal phase: SPICE versus the Interface Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer. We summarise how these observations can be coordinated.

Movies associated to Fig. 1 are available at https://www.aanda.org Title: Solar prominence diagnostics from non-LTE modelling of Mg II h&k line profiles Authors: Peat, A. W.; Labrosse, N.; Schmieder, B.; Barczynski, K. Bibcode: 2021A&A...653A...5P Altcode: 2021arXiv210610351P
Aims: We investigate a new method to for obtaining the plasma parameters of solar prominences observed in the Mg II h&k spectral lines by comparing line profiles from the IRIS satellite to a bank of profiles computed with a one-dimensional non-local thermodynamic equilibrium (non-LTE) radiative transfer code.
Methods: Using a grid of 1007 one-dimensional non-LTE radiative transfer models, some including a prominence-corona transition region (PCTR), we carry out this new method to match computed spectra to observed line profiles while accounting for line core shifts not present in the models. The prominence observations were carried out by the IRIS satellite on 19 April 2018.
Results: The prominence is very dynamic with many flows, including a large arm extending from the main body seen near the end of the observation. This flow is found to be redshifted, as is the prominence overall. The models are able to recover satisfactory matches in areas of the prominence where single line profiles are observed. We recover: mean temperatures of 6000-50 000 K; mean pressures of 0.01-0.5 dyne cm−2; column masses of 3.7 × 10−8-5 × 10−4 g cm−2; a mean electron density of 7.3 × 108-1.8 × 1011 cm−3; and an ionisation degree nHII/nHI = 0.03 − 4500. The highest values for the ionisation degree are found in areas where the line of sight crosses mostly plasma from the PCTR, correlating with high mean temperatures and correspondingly no Hα emission.
Conclusions: This new method naturally returns information on how closely the observed and computed profiles match, allowing the user to identify areas where no satisfactory match between models and observations can be obtained. The inclusion of the PCTR was found to be important when fitting models to data as regions where satisfactory fits were found were more likely to contain a model encompassing a PCTR. The line core shift can also be recovered from this new method, and it shows a good qualitative match with that of the line core shift found by the quantile method. This demonstrates the effectiveness of the approach to line core shifts in the new method.

Movies associated to Figs. 10 and A.1 are available at https://www.aanda.org Title: Vector Velocities Measurements with the Solar Orbiter SPICE Spectrometer Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini, C.; Auchère, F.; Berghmans, D.; Buchlin, E.; Dolla, L.; Mierla, M.; Parenti, S.; Rodriguez, L. Bibcode: 2021AAS...23831312P Altcode: The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving the ecliptic plane, opens up opportunities for the combined analysis of measurements obtained by solar imagers and spectrometers. For the first time, different spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere. Here we develop a methodology to prepare for this kind of analysis, by using data from the Hinode mission and the Solar Dynamics Observatory, respectively. We employ solar rotation to simulate measurements of spectrometers with different views of the solar corona. The resulting data allow us to apply stereoscopic tie-pointing and triangulation techniques designed for the STEREO spacecraft pair, and to perform 3D analysis of the Doppler shifts of a quasi-stationary active region. Our approach allows the accurate reconstruction of 3D velocity vectors in plasma flows along "open" and "closed" magnetic loops. This technique will be applied to the actual situation of two spacecraft at different separations with spectrometers on board (the Solar Orbiter Spectral Imaging of the Coronal Environment versus the Interface Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer) and we summarise how these observations can be coordinated to assess vector velocity measurements. This 3D spectroscopy method will facilitate the understanding of the complex flows that take place throughout the solar atmosphere. Title: The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2 Authors: Harra, L.; Brooks, D. H.; Bale, S. D.; Mandrini, C. H.; Barczynski, K.; Sharma, R.; Badman, S. T.; Vargas Domínguez, S.; Pulupa, M. Bibcode: 2021A&A...650A...7H Altcode: 2021arXiv210204964H Context. We investigated the source of a type III radio burst storm during encounter 2 of NASA's Parker Solar Probe (PSP) mission.
Aims: It was observed that in encounter 2 of NASA's PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019. Our aim is to investigate the source of these small and frequent bursts.
Methods: In order to do this, we analysed data from the Hinode EUV Imaging Spectrometer, PSP FIELDS, and the Solar Dynamics Observatory Atmospheric Imaging Assembly. We studied the behaviour of active region 12737, whose emergence and evolution coincides with the timing of the radio noise storm and determined the possible origins of the electron beams within the active region. To do this, we probed the dynamics, Doppler velocity, non-thermal velocity, FIP bias, and densities, and carried out magnetic modelling.
Results: We demonstrate that although the active region on the disc produces no significant flares, its evolution indicates it is a source of the electron beams causing the radio storm. They most likely originate from the area at the edge of the active region that shows strong blue-shifted plasma. We demonstrate that as the active region grows and expands, the area of the blue-shifted region at the edge increases, which is also consistent with the increasing area where large-scale or expanding magnetic field lines from our modelling are anchored. This expansion is most significant between 1 and 4 April 2019, coinciding with the onset of the type III storm and the decrease of the individual burst's peak frequency, indicating that the height at which the peak radiation is emitted increases as the active region evolves. Title: A Comparison of the Active Region Upflow and Core Morphologies Using Simultaneous Spectroscopic Observations from IRIS and Hinode. Authors: Barczynski, K.; Harra, L. K.; Kleint, L.; Panos, B. Bibcode: 2020AGUFMSH004..05B Altcode: The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of the active region are the source of the plasma outflow, and therefore contribute to the slow solar wind . However, the origin and morphology of the upflow region remain open questions. We investigated how the plasma properties (flux, Doppler velocity, and non-thermal velocity) change throughout the solar atmosphere, from the chromosphere via the transition region to the corona. We compared the upflow region and the core of an active region. We studied limb-to-limb observation of the active region (NOAA 12687) obtained between 14th and 25th November 2017. We analyzed spectroscopic data simultaneously obtained from Hinode/EIS and IRIS in six wavelengths (MgII, CII, SiIV, FeXII, FeXIII, and FeXIV). After the high-precision alignment (accuracy of the Hinode pixel size) of the raster maps, we studied the mutual relation between the plasma properties for each line, as well as compared the plasma properties in the close formation temperature lines. To find the most characteristic spectra, we classified the spectra in each wavelength using the machine learning technique k-means . We found that the fluxes of the lines formed in the close temperatures are highly correlated in the chromosphere via transition region to the corona. In the corona, the Doppler velocities are well correlated too. Despite high-correlation between the transition region and coronal fluxes, the Doppler velocities are independent in our active region. In coronal lines, the average non-thermal velocity is higher in the upflow region than the active region core. In the transition region, the velocities are similar; thus the non-thermal motions are essential in the coronal upflow. We found several mutual relations between the plasma parameters in different spectral lines. These relations and the spectra classification results suggest that the plasma upflow begins in the solar corona, but the nature of the upflow region can be determined from the underlying layers. Title: Dynamics and Flows in Active Region NOAA12737 that can contribute to Type III Bursts observed by Parker Solar Probe during Encounter 2. Authors: Harra, L.; Brooks, D.; Barczynski, K.; Mandrini, C. H.; Vargas-Dominguez, S.; Bale, S.; Badman, S. T.; Raouafi, N. E.; Rouillard, A. P. Bibcode: 2020AGUFMSH0240001H Altcode: We have analysed solar activity on the Sun during encounter 2 of the Parker Solar Probe mission. We studied the period from 30th March to 4th April when a small active region (NOAA 12737) emerged. This active region showed no significant flaring. During this time period there were however, an increasing number of type III bursts measured by the FIELDS instrument. We analyse solar data from SDO-AIA, SDO-HMI and Hinode EIS to determine what the potential sources of the type III bursts could be, which occur on timescales of tens of seconds. The active region core shows small brightenings in EUV and X-ray wavebands, but these are not continuous, and seem unlikely to be connected. There are magnetic field changes due to the active region emergence, which occur on timescales of hours rather than seconds. There are small scale magnetic flux emergences but these are not frequent enough to be linked to the continuous type III bursts. As the active region emerges, we track the upflows at the edge of the active region as they are created and evolve. We show evidence of variations in the upflows that seem to be the most likely candidates for the sources of the type III bursts. Title: Stereoscopic Measurements of Coronal Doppler Velocities Authors: Podladchikova, O.; Harra, L. K.; Barczynski, K.; Mandrini, C. H.; Auchere, F.; Buchlin, E.; Dolla, L.; Mierla, M.; Rodriguez, L. Bibcode: 2020AGUFMSH038..07P Altcode: The Solar Orbiter mission, whose orbit is outside the Sun-Earth line, opens up novel opportunities for the combined analysis of measurements by solar imagers and spectrometers. For the first time different spectrometers will be located at wide angles with each other allowing 3D spectroscopy in the solar atmosphere. In order to develop a methodology for these opportunities we make use of the Hinode EUV Imaging Spectrometer (EIS) and Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) and by employing solar rotation we simulate the measurements of two spectrometers that have different views of solar corona. The resulting data allows us to apply stereoscopic tie-pointing and triangulation techniques designed for SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suite on the STEREO (Solar Terrestrial Relations Observatory) spacecraft pair and perform three-dimensional analysis of Doppler shifts of quasi-stationary active region. We present a technique that allows the accurate reconstruction of the 3D velocity vector in plasma flows along open and closed magnetic loops. This technique will be applied to the real situation of two spacecraft at different separations with spectrometers onboard. This will include the Solar Orbiter Spectral Imaging of the Coronal Environment (SPICE), the Solar Orbiter Extreme Ultraviolet Imager (EUI),the Interface Region Imaging Spectrograph (IRIS) and Hinode EIS spectrometers and we summarise how these can be coordinated. This 3D spectroscopy is a new research domain that will aid the understanding of the complex flows that take place throughout the solar atmosphere. Title: Emission of solar chromospheric and transition region features related to the underlying magnetic field Authors: Barczynski, K.; Peter, H.; Chitta, L. P.; Solanki, S. K. Bibcode: 2018A&A...619A...5B Altcode: 2018arXiv180702372B Context. The emission of the upper atmosphere of the Sun is closely related to magnetic field concentrations at the solar surface.
Aims: It is well established that this relation between chromospheric emission and magnetic field is nonlinear. Here we investigate systematically how this relation, characterised by the exponent of a power-law fit, changes through the atmosphere, from the upper photosphere through the temperature minimum region and chromosphere to the transition region.
Methods: We used spectral maps from the Interface Region Imaging Spectrograph (IRIS) covering Mg II and its wings, C II, and Si IV together with magnetograms and UV continuum images from the Solar Dynamics Observatory. After a careful alignment of the data we performed a power-law fit for the relation between each pair of observables and determine the power-law index (or exponent) for these. This was done for different spatial resolutions and different features on the Sun.
Results: While the correlation between emission and magnetic field drops monotonically with temperature, the power-law index shows a hockey-stick-type variation: from the upper photosphere to the temperature-minimum it drops sharply and then increases through the chromosphere into the transition region. This is even seen through the features of the Mg II line, this is, from k1 to k2 and k3. It is irrespective of spatial resolution or whether we investigate active regions, plage areas, quiet Sun, or coronal holes.
Conclusions: In accordance with the general picture of flux-flux relations from the chromosphere to the corona, above the temperature minimum the sensitivity of the emission to the plasma heating increases with temperature. Below the temperature minimum a different mechanism has to govern the opposite trend of the power-law index with temperature. We suggest four possibilities, in other words, a geometric effect of expanding flux tubes filling the available chromospheric volume, the height of formation of the emitted radiation, the dependence on wavelength of the intensity-temperature relationship, and the dependence of the heating of flux tubes on the magnetic flux density. Title: Miniature loops in the solar corona Authors: Barczynski, K.; Peter, H.; Savage, S. L. Bibcode: 2017A&A...599A.137B Altcode: 2016arXiv161108513B Context. Magnetic loops filled with hot plasma are the main building blocks of the solar corona. Usually they have lengths of the order of the barometric scale height in the corona that is 50 Mm.
Aims: Previously it has been suggested that miniature versions of hot loops exist. These would have lengths of only 1 Mm barely protruding from the chromosphere and spanning across just one granule in the photosphere. Such short loops are well established at transition region temperatures (0.1 MK), and we investigate if such miniature loops also exist at coronal temperatures (>1 MK).
Methods: We used extreme UV (EUV) imaging observations from the High-resolution Coronal Imager (Hi-C) at an unprecedented spatial resolution of 0.3'' to 0.4''. Together with EUV imaging and magnetogram data from the Solar Dynamics Observatory (SDO) and X-Ray Telescope (XRT) data from Hinode we investigated the spatial, temporal and thermal evolution of small loop-like structures in the solar corona above a plage region close to an active region and compared this to a moss area within the active region.
Results: We find that the size, motion and temporal evolution of the loop-like features are consistent with photospheric motions, suggesting a close connection to the photospheric magnetic field. Aligned magnetograms show that one of their endpoints is rooted at a magnetic concentration. Their thermal structure, as revealed together with the X-ray observations, shows significant differences to moss-like features.
Conclusions: Considering different scenarios, these features are most probably miniature versions of hot loops rooted at magnetic concentrations at opposite sides of a granule in small emerging magnetic loops (or flux tubes). Title: Dynamics of polar plumes observed during the total solar eclipse of August 1, 2008 Authors: Bělík, M.; Rušin, V.; Saniga, M.; Barczynski, K. Bibcode: 2012CoSka..42..125B Altcode: We study dynamics of polar plumes observed during the 2008 eclipse from three ground-based sites and the Hinode satellite. The speed of apparent upward propagation, as inferred from the changes of brightness within each plume, is found to lie in the range from 30 to 100 km s-1. Some white-light plumes located in polar coronal holes were identified with their X-ray counterparts observed by the Hinode satellite, which showed almost the same speed. Title: Polar plumes dynamics observed during total solar eclipses Authors: Barczynski, K.; Bělík, M.; Marková, E. Bibcode: 2010nspm.conf..134B Altcode: Following the successful observation of significant activity in the polar plume during the total solar eclipse in 2006, the analysis of the Sun's polar regions was also carried out in the images obtained in multi-station observations of the eclipse of 2008. In this work polar plumes showing similar although much less significant manifestation of the dynamics have been identified. The dynamics evolution rates have been obtained from comparing the pictures taken at different times. The results are compared with the corresponding phenomena observed in X-rays from the HINODE satellite.