A5004575215- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Atmospheric Ozone and Climate
- X-ray Spectroscopy and Fluorescence Analysis
- Geophysics and Gravity Measurements
- Magnetic confinement fusion research
- Statistical Mechanics and Entropy
- Electron and X-Ray Spectroscopy Techniques
- Tropical and Extratropical Cyclones Research
- Gamma-ray bursts and supernovae
- Calibration and Measurement Techniques
- Image and Signal Denoising Methods
- Oil, Gas, and Environmental Issues
- Thermography and Photoacoustic Techniques
- Color Science and Applications
- Statistical and numerical algorithms
- Superconducting Materials and Applications
- solar cell performance optimization
- Impact of Light on Environment and Health
- CCD and CMOS Imaging Sensors
Czech Academy of Sciences, Astronomical Institute
2015-2024
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2012-2017
Université de Versailles Saint-Quentin-en-Yvelines
2017
Sorbonne Université
2017
Université Paris Cité
2008-2017
Observatoire de Paris
2017
Centre National de la Recherche Scientifique
2017
Délégation Paris 7
2008-2017
University of Cambridge
2013-2015
Czech Academy of Sciences
2012-2015
We present SDO/AIA observations of an eruptive X-class flare July 12, 2012, and compare its evolution with the predictions a 3D numerical simulation. focus on dynamics loops that are seen to undergo slipping reconnection during flare. In AIA 131A observations, lower parts 10 MK exhibit apparent motion velocities several tens km/s along developing ribbons. early stages flare, ribbons consist compact, localized bright transition-region emission from footpoints loops. A DEM analysis shows have...
ABSTRACT We investigate the occurrence of slipping magnetic reconnection, chromospheric evaporation, and coronal loop dynamics in 2014 September 10 X-class flare. Slipping reconnection is found to be present throughout flare from its early phase. Flare loops are seen slip opposite directions toward both ends ribbons. Velocities 20–40 km s −1 within time windows where well resolved. The warm exhibit expanding contracting motions that interpreted as displacements due growing flux rope...
We present the study of X2-class flare which occurred on 27 October 2014 and was observed with Interface Region Imaging Spectrograph (IRIS) EUV Spectrometer (EIS) board Hinode satellite. Thanks to high cadence spatial resolution IRIS EIS instruments, we are able compare simultaneous observations \xxi~1354.08~\AA~and \xxiii~263.77~\AA~high temperature emission ($\gtrsim$ 10~MK) in ribbon during chromospheric evaporation phase. find that observes completely blue-shifted \xxi~line profiles, up...
We study a polar-crown prominence with bubble and its plume observed in several coronal filters by the SDO/AIA Hα MSDP spectrograph Białków (Poland) to address following questions: what is brightness of bubbles EUV respect corona outside cavity? What geometry topology magnetic field bubble? nature vertical threads seen within prominences? find that lower than prominence, similar cavity. constructed linear force-free models prominences bubbles, where flux rope perturbed inclusion parasitic...
The non-Maxwellian $\kappa$-distributions have been detected in the solar transition region and flares. These distributions are characterized by a high-energy tail near-Maxwellian core known to significant impact on resulting optically thin spectra arising from collisionally dominated astrophysical plasmas. We developed KAPPA package (http://kappa.asu.cas.cz) for synthesis of such line continuum spectra. is based freely available CHIANTI database software, can be used similar manner....
The formation of the transition region O iv and Si lines observable by Interface Region Imaging Spectrograph (IRIS) is investigated for both Maxwellian non-Maxwellian conditions characterized a κ-distribution exhibiting high-energy tail. are formed at lower temperatures than all κ. In situations with κ, contribution functions shifted to temperatures. Combined slope differential emission measure, it possible be very different regions solar lines; possibly close chromosphere. Such might...
The intensity of the \oiv~2s$^{2}$ 2p $^{2}$P-2s2p$^{2}$ $^{4}$P and \siv~3 s$^{2}$ 3p $^{2}$P- 3s 3p$^{2}$ $^{4}$ P intercombination lines around 1400~\AA~observed with \textit{Interface Region Imaging Spectrograph} (IRIS) provide a useful tool to diagnose electron number density ($N_\textrm{e}$) in solar transition region plasma. We measure variety features observed by IRIS, including an active (AR) loop, plage brightening, ribbon 22-June-2015 M 6.5 class flare. By using emissivity ratios...
Abstract We analyze the spectra of high-temperature Fe xxiv lines observed by Hinode /Extreme-Ultraviolet Imaging Spectrometer (EIS) during impulsive phase X8.3-class flare on 2017 September 10. The line profiles are broad, show pronounced wings, and clearly depart from a single-Gaussian shape. can be well fitted with κ distributions, values varying between ≈1.7 3. regions where we observe non-Gaussian coincide location high-energy (≈100–300 keV) hard X-ray (HXR) sources RHESSI , suggesting...
In  standard  2D eruption models, the of a magnetic flux rope is associated with reconnection occurring beneath it. However, in 3D context, additional possibilities arise, particularly involving interactions between and overlying arcades. This process results drifting legs erupting rope.We show examples such reconnections filaments interacting coronal arcades, called ar-rf (arcade + – flare loop), using AIA/SDO IRIS data.To understand physical processes behind...
New data for the calculation of ionization and recombination rates have been published in past few years, most which are included CHIANTI database. We used these to calculate collisional non-Maxwellian κ-distributions with an enhanced number particles high-energy tail, detected solar transition region wind. Ionization equilibria elements H Zn derived. The significantly influence both widen ion abundance peaks. In comparison Maxwellian distribution, peaks can also be shifted lower or higher...
The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment launched on July 30, 2021 from the White Sands Missile Range in New Mexico. MaGIXS is a unique solar observing telescope developed to capture spectral images, 6 - 24 Angstrom wavelength range, of coronal active regions. Its novel design takes advantage recent technological advances related fabricating and optimizing optical systems as well breakthroughs inversion methodologies necessary create spectrally...
Aims. The aim of this work is to analyse the multi-instrument observations June 22, 2010 prominence study its structure in detail, including prominence-corona transition region and dark bubble located below body.
We report on the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and Hinode/EUV Spectrograph (EIS) observations of a transient coronal loop. The loop brightens up in same location after disappearance an arcade formed during B8.9-class microflare 3 hr earlier. EIS captures this its brightening phase, as observed most AIA filters. use data to study evolution loop, well perform differential emission measure (DEM) diagnostics function κ. Fe xi–Fe xiii lines by are used electron...
We investigate the possibility of diagnosing degree departure from Maxwellian distribution using single-ion spectra originating in astrophysical plasmas collisional ionization equilibrium. New atomic data for excitation Fe IX-XIII are integrated under assumption a kappa-distribution electron energies. Diagnostic methods lines single ion formed at any wavelength explored. Such minimize uncertainties and recombination rates, as well possible presence non-equilibrium ionization. Approximations...
Three homologous C-class flares and one last M-class flare were observed by both the Solar Dynamics Observatory (SDO) Hinode EUV Imaging Spectrometer (EIS) in AR 11429 on March 9, 2012. All recurrent occurred within a short interval of time (less than 4 hours), showed very similar plasma morphology all confined, until when large-scale eruption occurred. The are characterized appearance, at approximatively same locations, two bright compact footpoint sources $\approx$~3--10~MK evaporating...
We analyze the imaging observations of an M-class eruptive flare 2015 November, 4. The pre-eruptive H alpha filament was modelled by non-linear force free field model, which showed that it consisted two helical systems. Tether-cutting reconnection involving these systems led to formation a hot sigmoidal loop structure rooted in small hook formed at end ribbon. Subsequently, loops started slip away form until disappeared. continued slipping and ribbon elongated itself several tens arc...
Existing 3D extensions to the standard model show that flux-rope footpoints are surrounded by curved-shaped QSL-footprints can be related with hook-shaped flare-ribbons. We build upon this finding and further address joint questions of their time-evolution, formation flare loops at ends flaring PILs erupting bipole, which both relevant for understanding in general ICME studies particular. calculate QSLs field lines an MHD simulation a torus-unstable flux-rope. The evolving QSL footprints...
We report on observations of the two newly-identified reconnection geometries involving erupting flux ropes. In 3D, a rope can reconnect either with surrounding coronal arcade (recently named "ar-rf" reconnection) or itself ("rr-rf" reconnection), and both kinds create new field line flare loop. For first time, we identify all four constituents reconnections in solar eruptive event, filament eruption 2011 June 07 observed by SDO/AIA. The ar-rf manifests as shift one leg more than 25"...
Abstract Eruptive flares are sudden releases of magnetic energy that involve many phenomena, several which can be explained by the standard 2D flare model and its realizations in 3D. We analyze a 3D magnetohydrodynamics simulation, framework this model, naturally explains contraction coronal loops proximity sites, as well inflow toward region above cusp-shaped loops. find two vorticity arcs located along flanks erupting flux rope generated soon eruption begins. The arcades legs then...
Context. The non-Maxwellian κ-distributions have been detected in the solar wind and can explain intensities of some transition region lines. Presence such distributions outer layers atmosphere influences ionization excitation equilibrium widens line contribution functions. This behavior may be reflected on reconstructed differential emission measure (DEM).
Spectroscopic observations made by the Extreme Ultraviolet Variability Experiment (EVE) on board Solar Dynamics Observatory (SDO) during 2012 March 7 X5.4-class flare (SOL2012-03-07T00:07) are analyzed for signatures of non-Maxwellian kappa-distributions. Observed spectra were averaged over 1 minute to increase photon statistics in weaker lines and pre-flare spectrum was subtracted. Synthetic line intensities kappa-distributions calculated using KAPPA database. We find strong departures...
Abstract We report on observations of the conversion bright filament strands into flare loops during 2012 August 31 eruption. Prior to eruption, individual composing one legs were observed in 171 Å filter channel data Atmospheric Imaging Assembly. After onset hooked ribbons started propagate and contract, sweeping footpoints as well coronal located close by. Later on, hot appeared regions swept by hook, where rooted. Timing localization these phenomena suggest that they are caused...