Publications (44)
Chromospheric resonances above sunspots and potential seismological applications
T. Felipe, C. Kuckein, S. J. González Manrique +2
Oscillations in sunspot umbrae exhibit remarkable differences between the photosphere and chromosphere. We evaluate two competing scenarios proposed for explaining those observatio…
Numerical determination of the cutoff frequency in solar models
T. Felipe, C. R. Sangeetha
In stratified atmospheres, acoustic waves can only propagate if their frequency is above the cutoff value. Different theories provide different cutoff values. We developed an alter…
Dependence of sunspot photospheric waves on the depth of the source of solar modes
T. Felipe, E. Khomenko
Photospheric waves in sunspots moving radially outwards at speeds faster than the characteristic wave velocities have been recently detected. It has been suggested that they are th…
Evaluation of the capability of local helioseismology to discern between monolithic and spaghetti sunspot models
T. Felipe, A. D. Crouch, A. C. Birch
The helioseismic properties of the wave scattering generated by monolithic and spaghetti sunspots are analyzed by means of numerical simulations. In these computations, an incident…
Helioseismic Holography of Simulated Sunspots: dependence of the travel time on magnetic field strength and Wilson depression
T. Felipe, D. C. Braun, A. C. Birch
Improving methods for determining the subsurface structure of sunspots from their seismic signature requires a better understanding of the interaction of waves with magnetic field…
Mancha3D code: Multi-purpose Advanced Non-ideal MHD Code for High resolution simulations in Astrophysics
M. Modestov, E. Khomenko, N. Vitas +14
The Mancha3D code is a versatile tool for numerical simulations of magnetohydrodynamic processes in solar/stellar atmospheres. The code includes non-ideal physics derived from plas…
Spiral-shaped wavefronts in a sunspot umbra
T. Felipe, C. Kuckein, E. Khomenko +1
Solar active regions show a wide variety of oscillatory phenomena. The presence of the magnetic field leads to the appearance of several wave modes, whose behavior is determined by…
Three-dimensional numerical simulations of fast-to-Alfven conversion in sunspots
T. Felipe
The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wa…
Chromospheric velocities in an M3.2 flare using He I 1083.0 nm and Ca II 854.2 nm
C. Kuckein, M. Collados, A. Asensio Ramos +6
We study the chromospheric LOS velocities during the GOES M3.2 flare (SOL2013-05-17T08:43) using simultaneous spectroscopic data of the He I 1083.0 nm triplet and Ca II 854.2 nm li…
Synthetic polarimetric spectra from stellar prominences
T. Felipe, M. J. MartÃnez González, A. Asensio Ramos
Stellar prominences detected in rapidly rotating stars serve as probes of the magnetism in the corona of cool stars. We have synthesized the temporal evolution of the Stokes profil…
Numerical simulations of multiple scattering of the mode by flux tubes
T. Felipe, A. D. Crouch, A. C. Birch
We use numerial simulations to study the absorption and phase shift of surface-gravity waves caused by groups of magnetic flux tubes. The dependence of the scattering coefficients…
Mode transformation and frequency change with height in 3D numerical simulations of magneto-acoustic wave propagation in sunspots
T. Felipe, E. Khomenko, M. Collados
Three-dimensional numerical simulations of magnetoacoustic wave propagation are performed in a sunspot atmosphere with a computational domain covering from the photosphere to the c…
Two fluid dynamics in solar prominences
S. J. González Manrique, E. Khomenko, M. Collados +3
Solar prominences contain a significant amount of neutral species. The dynamics of the ionised and neutral fluids composing the prominence plasma can be slightly different if the c…
Non-linear numerical simulations of magneto-acoustic wave propagation in small-scale flux tubes
E. Khomenko, M. Collados, T. Felipe
We present results of non-linear, 2D, numerical simulations of magneto-acoustic wave propagation in the photosphere and chromosphere of small-scale flux tubes with internal structu…
Magneto-acoustic waves in sunspots: first results from a new 3D nonlinear magnetohydrodynamic code
T. Felipe, E. Khomenko, M. Collados
Waves observed in the photosphere and chromosphere of sunspots show complex dynamics and spatial patterns. The interpretation of high-resolution sunspot wave observations requires…
Synthetic observations of wave propagation in a sunspot umbra
T. Felipe, H. Socas-Navarro, E. Khomenko
Spectropolarimetric temporal series from Fe I 6301.5 Ã and Ca II infrared triplet lines are obtained by applying the Stokes synthesis code NICOLE to a numerical simulation of…
Improving the Understanding of Subsurface Structure and Dynamics of Solar Active Regions (A white paper submitted to the decadal survey for solar and space Physics (Heliophysics) -- SSPH 2024-2033)
S. C. Tripathy, K. Jain, D. Braun +14
The goal of helioseismology is to provide accurate information about the Sun's interior from the observations of the wave field at its surface. In the last three decades, both glob…
Modeling Solar Atmosphere Dynamics with MAGEC
AnamarÃa Navarro, E. Khomenko, N. Vitas +1
Modeling the solar atmosphere is challenging due to its layered structure and multi-scale dynamics. We aim to validate the new radiative MHD code MAGEC, which combines the MANCHA a…
Magnetic field fluctuations in the shocked umbral chromosphere
T. Felipe, S. J. González Manrique, C. R. Sangeetha +1
Several studies have reported magnetic field fluctuations associated with umbral shock waves. We aim to study the properties and origin of magnetic field fluctuations in the umbral…
Performance of solar far-side active regions neural detection
E. G. Broock, T. Felipe, A. Asensio Ramos
Context. Far-side helioseismology is a technique used to infer the presence of active regions in the far hemisphere of the Sun based on the interpretation of oscillations measured…
Helioseismic holography of simulated sunspots: magnetic and thermal contributions to travel times
T. Felipe, D. C. Braun, A. D. Crouch +1
Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that o…
Observational signatures of numerically simulated MHD waves in small-scale fluxtubes
E. Khomenko, M. Collados, T. Felipe
We present some results obtained from the synthesis of Stokes profiles in small-scale flux tubes with propagating MHD waves. To that aim, realistic flux tubes showing internal stru…
Signatures of sunspot oscillations and the case for chromospheric resonances
T. Felipe
Sunspots host a large variety of oscillatory phenomena, whose properties depend on the nature of the wave modes and the magnetic and thermodynamic structure of the spot. Umbral chr…
Improved detection of farside solar active regions using deep learning
T. Felipe, A. Asensio Ramos
The analysis of waves in the visible side of the Sun allows the detection of active regions in the farside through local helioseismology techniques. The knowledge of the magnetism…
Magneto-acoustic waves in sunspots from observations and numerical simulations
T. Felipe, E. Khomenko, M. Collados +1
We study the propagation of waves from the photosphere to the chromosphere of sunspots. From time series of cospatial Ca II H (including its line blends) intensity spectra and pola…
Multi-wavelength spectropolarimetric observations of AR13724 performed by GRIS
C. Quintero Noda, J. C. Trelles Arjona, T. del Pino Alemán +10
Multi-line spectropolarimetric observations allow for the simultaneous inference of the magnetic field at different layers of the solar atmosphere and provide insight into how thes…
Scattering of the f-mode by small magnetic flux elements from observations and numerical simulations
T. Felipe, D. C. Braun, A. D. Crouch +1
The scattering of f-modes by magnetic tubes is analyzed using three-dimensional numerical simulations. An f-mode wave packet is propagated through a solar atmosphere embedded with…
Multiple Stokes I inversions to infer magnetic fields in the spectral range around Cr I 5782 Ã
C. Kuckein, H. Balthasar, C. Quintero Noda +8
The spectral window, containing Fraunhofer lines formed in the solar photosphere, around the magnetically sensitive Cr I lines at 5780.9, 5781.1, 5781.7, 5783.0, and 5783.8 Ã , wit…
Solar vortex detection methods in MHD simulations: impact of magnetic field and spatial resolution
M. Koll Pistarini, E. Khomenko, T. Felipe +1
The aim of this paper is to investigate the influence of different magnetic field configurations and spatial resolutions on vortex structures. We analyzed a set of six three-dimens…
Inversions of synthetic umbral flashes: effects of the scanning time on the inferred atmospheres
T. Felipe, H. Socas-Navarro, D. Przybylski
The use of instruments that record narrow band images at selected wavelengths is a common approach in solar observations. They allow the scanning of a spectral line by sampling the…
Signatures of the impact of flare ejected plasma on the photosphere of a sunspot light-bridge
T. Felipe, M. Collados, E. Khomenko +4
We investigate the properties of a sunspot light-bridge, focusing on the changes produced by the impact of a plasma blob ejected from a C-class flare. We observed a sunspot in acti…
Vortex Flows in the Solar Atmosphere: Detection and Heating Mechanisms in 3D MHD Numerical Simulations
M. Koll Pistarini, E. Khomenko, T. Felipe
Vortex flows are structures associated with the rotation of the plasma and/or the magnetic field that are present throughout the solar atmosphere. In recent years, their study has…
Downflowing umbral flashes as an evidence of standing waves in sunspot umbrae
T. Felipe, V. M. J. Henriques, J. de la Cruz RodrÃguez +1
Umbral flashes are sudden brightenings commonly visible in the core of chromospheric lines. Theoretical and numerical modeling suggest that they are produced by the propagation of…
Origin of the chromospheric three-minute oscillations in sunspot umbrae
T. Felipe
Sunspot umbrae show a change in the dominant period of their oscillations from five minutes in the photosphere to three minutes in the chromosphere. In this paper, we explore the t…
Seismic Monitoring of the Sun's Far Hemisphere: A Crucial Component in Future Space Weather Forecasting (A White Paper Submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) -- SSPH 2024-2033)
Kiran Jain, C. Lindsey, E. Adamson +20
The purpose of this white paper is to put together a coherent vision for the role of helioseismic monitoring of magnetic activity in the Sun's far hemisphere that will contribute t…
FarNet-II: An improved solar far-side active region detection method
E. G. Broock, A. Asensio Ramos, T. Felipe
Context. Activity on the far side of the Sun is routinely studied through the analysis of the seismic oscillations detected on the near side using helioseismic techniques such as p…
Inversions of synthetic umbral flashes: selection of wavelength sampling
T. Felipe, S. Esteban Pozuelo
Imaging spectrographs are popular instruments used to obtain solar data. They record quasi-monochromatic images at selected wavelength positions. By scanning the spectral range of…
Impact of opacity effects on chromospheric oscillations inferred from NLTE inversions
T. Felipe, H. Socas-Navarro
Chromospheric inferences rely on the interpretation of spectral lines that are formed under Non-Local Thermodynamic Equilibrium (NLTE) conditions. In the presence of oscillations,…
Three-dimensional structure of a sunspot light bridge
T. Felipe, M. Collados, E. Khomenko +26
Active regions are the most prominent manifestations of solar magnetic fields; their generation and dissipation are fundamental problems in solar physics. Light bridges are commonl…
Observations of umbral flashes in the resonant sunspot chromosphere
T. Felipe, S. J. González Manrique, D. MartÃnez-Gómez +4
In sunspot umbrae, the core of some chromospheric lines exhibits periodic brightness enhancements known as umbral flashes. The consensus is that they are produced by the upward pro…
Multi-layer study of wave propagation in sunspots
T. Felipe, E. Khomenko, M. Collados +1
We analyze the propagation of waves in sunspots from the photosphere to the chromosphere using time series of co-spatial Ca II H intensity spectra (including its line blends) and p…
Limitations of the Ca II 8542 Ã line for the determination of magnetic field oscillations
T. Felipe, H. Socas Navarro, C. R. Sangeetha +1
Chromospheric umbral oscillations produce periodic brightenings in the core of some spectral lines, known as umbral flashes. They are also accompanied by fluctuations in velocity,…
Height variation of the cutoff frequency in a sunspot umbra
T. Felipe, C. Kuckein, I. Thaler
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-fr…
Magneto-acoustic wave energy from numerical simulations of an observed sunspot umbra
T. Felipe, E. Khomenko, M. Collados
We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through 3D MHD numerical simulations. A magneto-static sunspot…