A5078530603- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Magnetic confinement fusion research
- Fluid Dynamics and Turbulent Flows
- Stellar, planetary, and galactic studies
- Dust and Plasma Wave Phenomena
- Solar Radiation and Photovoltaics
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Tropical and Extratropical Cyclones Research
- Photovoltaic System Optimization Techniques
- Aeolian processes and effects
- History and Developments in Astronomy
- Polar Research and Ecology
- Elasticity and Material Modeling
- Rheology and Fluid Dynamics Studies
- Theoretical and Computational Physics
- Model Reduction and Neural Networks
- Global Energy and Sustainability Research
- Geophysics and Sensor Technology
- Reservoir Engineering and Simulation Methods
- Optical properties and cooling technologies in crystalline materials
University of Sheffield
2016-2025
Physical Sciences (United States)
2025
Konkoly Observatory
2017
Research Centre for Astronomy and Earth Sciences
2017
University of St Andrews
2002-2003
KU Leuven
1999-2001
Eötvös Loránd University
1998
The Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand and model the basic physical processes that control structure dynamics of Sun its atmosphere. first-light DKIST images, released publicly on 29 January 2020, only hint at extraordinary capabilities which accompany full commissioning five facility instruments. With this Critical Science Plan (CSP) we attempt anticipate some what those enable, providing a snapshot scientific pursuits hopes engage...
Abstract The nature of energy generation, transport, and effective dissipation responsible for maintaining a hot solar upper atmosphere is still elusive. Poynting flux vital parameter describing the direction magnitude flow, which mainly used in physics estimating upward generated by photospheric plasma motion. This study presents pioneering 3D mapping magnetic transport within numerically simulated atmosphere. By calculating Finite Time Lyapunov Exponent velocity, defined as ratio to...
Large-scale eruption events in the solar atmosphere can generate global waves, i.e., waves that propagate over distances comparable to radius. In low corona, observed by SOHO EIT, generated coronal mass ejections or flares, are usually referred as "EIT waves." The nature of these is subject strong debate, and opinions divided between different interpretations (e.g., fast magnetohydrodynamic shock nonwave feature, etc.). present Letter, we studied TRACE EUV data show disturbances indeed with...
Abstract Analysing high-resolution solar atmospheric observations requires robust techniques to recover plasma flow features across different scales, especially in active regions. Current methodologies often fall short capturing subgranular-scale flows, and there is limited research on the errors introduced by velocity estimation analysing properties of recovered flows presence kG magnetic flux density. This study concentrates validating effectiveness DeepVel neural network recovering...
Here we study the nature and characteristics of waves propagating in partially ionised plasmas weakly limit, typical for lower part solar atmosphere. The framework which properties are discussed depends on relative magnitude collisions between particles, but also collisional frequencies compared to gyro-frequency charged particles. Our investigation shows that atmospheric plasma can divided into two regions this division occurs, roughly, at base chromosphere. In photosphere is non-magnetised...
The most promising mechanism acting towards damping the kink oscillations of coronal loops is resonant absorption. In this context previous studies neglected effect obvious equilibrium flow along magnetic field lines. flows are in general sub-Alfv\'enic and hence comparatively slow. Here we investigate an on absorption linear MHD waves a cylindrical flux tube with aim determining changes frequency forward backward propagating modification times due to flow. A loop model both density...
We aim to investigate the properties of linear Alfv\'en and slow magnetoacoustic waves in a partially ionised plasma ionisation non-equilibrium. The propagation characteristics these are studied within framework two-fluid terms collisional strength between heavy particles for different degrees ionisation. In non-equilibrium state rates recombinations not equal. For analytical progress we assume background that is equilibrium, driven by perturbations system, {\bf therefore, effects related...
High-resolution solar observations show the complex structure of magnetohydrodynamic (MHD) wave motion. We apply techniques proper orthogonal decomposition (POD) and dynamic mode (DMD) to identify dominant MHD modes in a sunspot using intensity time series. The POD technique was used find that are spatially orthogonal, whereas DMD identifies temporal orthogonality. Here, we combined approaches can successfully both sausage kink umbra with an approximately circular cross-sectional shape. This...
Abstract In this paper, we provide clear direct evidence of multiple concurrent higher-order magnetohydrodynamic (MHD) modes in circular and elliptical sunspots by applying both proper orthogonal decomposition (POD) dynamic mode (DMD) techniques on solar observational data. These are well documented validated the areas fluid mechanics, hydraulics, granular flows but relatively new to field physics. While POD identifies based orthogonality space provides a ranking terms their contribution...
ABSTRACT Pores and sunspots are ideal environments for the propagation of guided magnetohydrodynamic (MHD) waves. However, modelling such photospheric waveguides with varying background quantities as plasma density magnetic field has thus far been very limited. Such is required to correctly interpret MHD waves observed in pores resolved inhomogeneities light bridges umbral dots. This study will investigate characteristics spatial structure slow body modes a flux tube circular cross-section...
Aims: On 13 June 1998, the TRACE satellite was fortuitously well placed to observe effects of a flare-induced EIT wave in corona, and its subsequent interaction with coronal magnetic loops. In this study, we use these observations corroborate previous theoretical work, as estimate field strength degree longitudinal inhomogeneity. Methods: Loop edges are tracked, both spatially temporally, using wavelet modulus maxima algorithms, corresponding loop displacements from quiescent state analysed...
Aims. In this paper, we aim to study the time dependence of sunspot group areas in a large sample composed various databases spanning over 130 years, used state-of-the-art statistical methods. Methods. For carefully selected but unbiased sample, use Bayesian modelling fit temporal evolution combined umbral and penumbral area spot groups with skew-normal function determine existence any asymmetry growth or decay. Our primary selection criteria guaranteed that only well-defined maximum were...
Abstract The electromagnetic energy flux in the lower atmosphere of Sun is a key tool to describe balance solar atmosphere. Current investigations on focus primarily vertical through photosphere, ignoring Poynting other directions and its possible contributions local heating. Based realistic Bifrost simulation quiet-Sun (coronal hole) atmosphere, we find that total photosphere occurs mainly parallel concentrating small regions along intergranular lanes. Thereby, it was define proxy for this...
Abstract The majority of studies on multi-scale vortex motions employ a two-dimensional geometry by using variety observational and numerical data. This approach limits the understanding nature physical processes responsible for dynamics. Here, we develop new methodology to extract essential information from boundary surface tubes. 3D high-resolution magneto-convection MURaM data has been used analyze photospheric intergranular velocity vortices. Lagrangian averaged vorticity deviation...
Abstract Through their lifetime, sunspots undergo a change in area and shape and, as they decay, fragment into smaller structures. Here, for the first time we analyze spatial structure of magnetohydrodynamic (MHD) slow-body fast-surface modes observed umbrae cross-sectional changes. The proper orthogonal decomposition (POD) dynamic mode (DMD) techniques were used to 3 6 hr Solar Dynamics Observatory/Helioseismic Magnetic Imager series Doppler velocities at photospheric level approximately...
The perturbations from the solar terminator in range of acoustic-gravity waves (AGWs) periods 5 minutes to 1 hour were analysed with use measurements VLF radio signals amplitudes on European path GQD–A118 (Great Britain–France). These observations provide information propagation at altitudes near mesopause (∼ 90 km), where are reflected. On considered a systematic increase fluctuations was observed within few hours after passage evening terminator. For April, June, October 2020 and February...
Abstract The phase mixing of Alfvén waves is one the most promising mechanisms for heating solar atmosphere. damping in this case requires small transversal scales, relative to magnetic field direction; requirement achieved by considering a inhomogeneity equilibrium plasma density profile. Using single-fluid approximation partially ionized chromospheric plasma, we study effectiveness phase-mixed shear and investigate effect varying ionization degree on dissipation waves. Our results show...
The solar coronal plasma is a well-known example of with strongly anisotropic dissipative coefficients. main processes in the corona are thermal conductivity and viscosity. Ruderman Goossens [Astrophys. J. 471, 1015 (1996)] developed linear theory driven slow resonant waves plasmas viscosity conductivity. Linear shows that layer amplitudes oscillations become very large for high Reynolds Pecklet numbers, so nonlinearity may be important. In present paper nonlinear behavior...
In the solar wind, effect of Hall current generated perpendicular to ambient magnetic field can influence plasma behaviour. particular, introduces wave dispersion which may compensate nonlinear steepening waves. presence viscosity, these effects lead a slowly decaying KdV soliton. Here we investigate solitary propagating obliquely an field. Our results show that slow magnetoacoustic wave, arises from steepening, propagates faster than linear mode speed; by contrast, fast slower speed. We...
The present paper aims to discuss the possible dissipative mechanisms acting in a coronal prominence. These mechanism are discussed within context of spatial damping linear compressional waves. obtained results show that dominant is thermal radiation provided supposition optically thin prominence valid. Damping due conduction viable attenuation wavelength waves short.
Aims. We study the generation of transversal oscillations in coronal loops represented as a straight thin flux tube under effect an external driver modelling global EIT wave. investigate how generated depend on nature driver, and type interaction between two systems.