A5066101535- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Magnetic confinement fusion research
- Solar Radiation and Photovoltaics
- Complex Systems and Time Series Analysis
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Earthquake Detection and Analysis
- Fluid Dynamics and Turbulent Flows
- Atmospheric Ozone and Climate
- Cancer, Hypoxia, and Metabolism
- Time Series Analysis and Forecasting
- Dust and Plasma Wave Phenomena
- Aerospace Engineering and Energy Systems
- Spacecraft and Cryogenic Technologies
- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Blood properties and coagulation
- Statistical and numerical algorithms
- Spectroscopy and Laser Applications
- CCD and CMOS Imaging Sensors
Universitat de les Illes Balears
2015-2024
Institute of Applied Computing & Community Code
2016-2024
Ramon.Space (Israel)
2004-2010
Universitat Ramon Llull
2005-2006
Fundació Universitat-Empresa de les Illes Balears
2001
University of Bristol
1997-1998
University of Edinburgh
1998
First results from a high-resolution three-dimensional nonlinear numerical study of the kink oscillation are presented. We show in detail development shear instability an untwisted line-tied magnetic flux tube. The produces significant deformations tube boundary. An extended transition layer may naturally evolve as result at sharp between and external medium. also discuss possible effects on process resonant absorption when inhomogeneous is included model. One implications these that...
Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics prominences has been subject a large number studies, and particular interest is study prominence oscillations. Ground- space-based observations have confirmed presence oscillatory motions in they interpreted terms magnetohydrodynamic (MHD) waves. This interpretation opens door to perform seismology, whose main aim determine physical parameters plasma (prominences) that difficult measure...
Abstract Rossby waves are a pervasive feature of the large-scale motions Earth’s atmosphere and oceans. These (also known as planetary r-modes) also play an important role in dynamics different astrophysical objects such solar interior, discs, rapidly rotating stars, exoplanetary atmospheres. This paper provides review theoretical observational aspects on spatial temporal scales various settings. The physical played by Rossby-type associated instabilities is discussed context stellar...
Apart from the eleven-year solar cycle, another periodicity around 155–160 days was discovered during cycle 21 in high-energy flares, and its presence sunspot areas strong magnetic flux has been also reported. This an elusive enigmatic character, since it usually appears only near maxima of cycles, seems to be related with a periodic emergence at surface. Therefore, is probably connected tachocline, thin layer located base convection zone, where dynamo field stored. We study dynamics Rossby...
ABSTRACT Coronal rain clumps and prominence knots are dense condensations with chromospheric to transition region temperatures that fall down in the much hotter corona. Their typical speeds range 30–150 km s −1 of order 10–30 , respectively, i.e., they considerably smaller than free-fall velocities. These cold blobs contain a mixture ionized neutral material must be dynamically coupled together, as observed. We investigate this coupling by means hydrodynamic simulations which arises from...
Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics prominences has been subject a large number studies, and particular interest is study prominence oscillations. Ground- space-based observations have confirmed presence oscillatory motions in they interpreted terms magnetohydrodynamic waves. This interpretation opens door to perform seismology, whose main aim determine physical parameters plasma (prominences) that difficult measure by...
The excitation and damping of transverse coronal loop oscillations is studied using a one-dimensional model line-tied cylindrical loop. By solving the time-dependent magnetohydrodynamic (MHD) equations, we show how an initial disturbance produced in solar corona induces kink-mode oscillations. We analyze effect on with nonuniform boundary layer investigate such due to resonant absorption. find that period attenuation time results agree calculations corresponding quasi-mode (i.e., kink mode...
Up to now, the periodic behaviour of N-S asymmetry solar activity has been analyzed by applying power spectrum analysis time series generated from a normalized definition asymmetry. Using sunspot areas and properties discrete Fourier transform, we show that use leads misleading results, correct be used is difference between values indicators in Northern Southern hemispheres. However, this case found significant periodicities correspond already present hemispheric series, not providing with...
Aims.The role of collisions between ions, electrons and neutrals in a partially ionised plasma is assessed as possible wave damping mechanism. The relevance this mechanism the small amplitude prominence oscillations evaluated.
The influence of a toroidal magnetic field on the dynamics Rossby waves in thin layer ideal conductive fluid rotating sphere is studied "shallow water" magnetohydrodynamic approximation for first time. Dispersion relations are derived analytically Cartesian and spherical coordinates. It shown that causes splitting low order (long wavelength) into two different modes, here denoted fast slow {\em waves}. high frequency mode (the mode) corresponds to an ordinary hydrodynamic wave slightly...
We study the excitation and damping of transverse oscillations in a multi-stranded model straight line-tied coronal loop. The geometry our equilibrium configuration is quite irregular more realistic than usual cylindrical loop model. By numerically solving time-dependent ideal magnetohydrodynamic equations two dimensions we show how global motion whole bundle strands, excited by an external disturbance, converted into localized Alfvénic motions due to process resonant absorption. This...
From recent high resolution observations obtained with the Swedish 1 m Solar Telescope in La Palma, we detect swaying motions of individual filament threads plane sky. The oscillatory character these are comparable Doppler signals from corresponding threads. Simultaneous recordings line sight and sky give information about orientation plane. These oscillations interpreted context magnetohydrodynamic theory. Kink waves supported by thread body proposed as an explanation observed oscillations....
Oscillations and propagating waves are commonly seen in high-resolution observations of filament threads, i.e., the fine-structures solar filaments/prominences. Since temperature prominences is typically order 10^4 K, prominence plasma only partially ionized. In this paper, we study effect neutrals on wave propagation a thread modeled as ionized homogeneous magnetic flux tube embedded an fully coronal plasma. Ohmic ambipolar diffusion considered basic resistive MHD equations. We numerically...
In this paper we present a numerical study of the time evolution solar prominences embedded in sheared magnetic arcades. The prominence is represented by density enhancement background-stratified atmosphere and connected to photosphere through field. By solving ideal magnetohydrodynamic equations three dimensions, dynamics for range parameters representative real prominences. Depending on considered, find that are suspended above photosphere, i.e., detached prominences, but also...
Abstract It has been proposed that Alfvén waves play an important role in the energy propagation through solar atmospheric plasma and its heating. Here we theoretically investigate of torsional magnetic flux tubes expanding from photosphere up to low corona explore reflection, transmission, dissipation wave energy. We use a realistic variation properties field strength with height. Dissipation by ion–neutral collisions chromosphere is included using multifluid partially ionized model....
Solar activity undergoes a variation over time scales of several months known as Rieger-type periodicity, which usually occurs near maxima sunspot cycles. An early analysis showed that the periodicity appears only in some cycles, and is absent other But appearance/absence during different cycles has not been explained. We performed wavelet data from Greenwich Royal Observatory Belgium 14-24. found periods occur all but they are cycle-dependent: shorter stronger Our revealed 185-195 days weak...
Some observations suggest that quiescent solar prominences can be considered as composed by small-scale loops, or fibrils, which are stacked one after another in both the vertical and horizontal directions. In a previous work we studied, Cartesian geometry, propagation of fast MHD waves two-dimensional magnetostatic model representing these fibrils. Since this is crude to represent real fibril, paper use more realistic based on cylindrically symmetric flux tube study structure. A new array...
Using time series of two-dimensional Dopplergrams, a temporal and spatial analysis oscillations in quiescent prominence has been performed. The presence an outstanding oscillatory signal the acquired data allowed us to study distribution wave motions and, particular, detect location generation anisotropic propagation perturbations from that place. Moreover, strong damping observed, with times between two three period. direction propagation, wavelength phase speed, together period, have...
A periodicity near 154 days was discovered in the number of high-energy solar flares detected by Solar Maximum Mission (SMM) and Geosynchronous Operational Environmental Satellites (GOES) during time interval 1980-1984 (Rieger et al.; Dennis). In this paper, we analyze historical records photospheric magnetic flux to show that cycle 21 appeared linked strong fields, while it absent 22. We also there a frequency coincidence between both periodicities 21, which suggests existence causal link...
We study the kink modes of oscillation a curved coronal loop using toroidal model with power-law density profile. find that there are two and their velocity polarization is either mainly horizontal or vertical respect to photosphere. It found damping by resonant absorption in an inhomogeneous layer between environment slightly more efficient than for straight magnetic cylinder period time very similar. In equilibrium nonuniform Alfvén frequency, display additional features, namely, coupling...