General
La simulación numérica mediante códigos complejos de ordenador es una herramienta fundamental en la investigación física y en la técnica desde hace décadas. El crecimiento vertiginoso de las capacidades informáticas junto con el avance notable de la matemática numérica ha hecho accesible a los centros de investigación de tamaño medio esta rama de la investigación, a caballo entre la física teórica y la física experimental. La astrofísica no es excepción a lo anterior, habiéndose desarrollado desde finales de los 70 una especialidad de la misma, la astrofísica computacional, que ha permitido llegar a comprender gran variedad de fenómenos inaccesibles a la investigación teórica pura y dar cuenta de observaciones hasta entonces inexplicadas. Su mayor campo de aplicación en las décadas pasadas han sido los fenómenos (magneto) hidrodinámicos y de dinámica de gases en multiplicidad de entornos cósmicos, por ejemplo los interiores y atmósferas estelares y planetarios y el medio interestelar, incluyendo magnetoconvección y dínamo, discos de acreción, evolución de nebulosas planetarias, explosiones y restos de supernova, etc. La incorporación a las simulaciones numéricas de las ecuaciones del transporte radiativo, ocurrida ya en décadas pasadas, ha permitido dotar de mayor realismo a los estudios de procesos hidrodinámicos en fotosferas y cromosferas estelares.
El presente Proyecto quiere apoyar el desarrollo en el IAC de la investigación astrofísica basada en el uso de grandes códigos numéricos que requieren el uso de ordenadores masivamente paralelos y su enlace con los resultados de observación. Objetivo general de este Proyecto es la realización de cálculos de física de fluidos cósmicos y de transporte radiativo. La temática de dichos cálculos se centrará en
- fenómenos de dinámica de gases magnetizados en interiores y atmósferas estelares
- transporte de radiación y señales de polarización en líneas espectrales en base a modelos atómicos y moleculares realistas y los efectos Hanle y Zeeman
- comparación de resultados teórico/numéricos con datos de observación
Este Proyecto es especialmente relevante a la vista de la involucración, cada vez mayor, del IAC en las redes de supercomputación nacionales y europeas y, en general, en grandes iniciativas de instalación de superordenadores.
Miembros
Resultados
- En las regiones del Sol en calma se observan diminutos lazos magnéticos emerger del interior de gránulos. Mediante simulaciones numéricas 3D se ha descubierto el proceso de formación de estas estructuras. Los resultados han sido publicados en el trabajo ApJ Letter 859, id. L26 liderado por Prof Fernando Moreno-Insertis.
- En una colaboración internacional se han catalogado casi 200 oscilaciones en protuberancias solares. Este es el primer estudio estadístico que se hace de estos eventos incluyendo una gran cantidad de oscilaciones de gran amplitud. El trabajo ha sido liderado por Dr Manuel Luna y publicado en ApJ Supplement Series, 236, id. 35.
Actividad científica
Publicaciones relacionadas
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Observational and numerical characterization of a recurrent arc-shaped front propagating along a coronal fan
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Ambipolar Diffusion in the Lower Solar Atmosphere: Magnetohydrodynamic Simulations of a Sunspot
Magnetohydrodynamic (MHD) simulations of the solar atmosphere are often performed under the assumption that the plasma is fully ionized. However, in the lower solar atmosphere a reduced temperature often results in only the partial ionization of the plasma. The interaction between the decoupled neutral and ionized components of such a partially
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The European Solar Telescope
The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes
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A 2D Model for Coronal Bright Points: Association with Spicules, UV Bursts, Surges, and EUV Coronal Jets
Coronal bright points (CBPs) are ubiquitous structures in the solar atmosphere composed of hot small-scale loops observed in extreme-ultraviolet (EUV) or X-rays in the quiet Sun and coronal holes. They are key elements to understanding the heating of the corona; nonetheless, basic questions regarding their heating mechanisms, the chromosphere
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Doppler-velocity Drifts Detected in a Solar Prominence
We analyzed multiline observations of a quiescent prominence from the slit spectrograph located at the Ondřejov Observatory. Dopplergrams and integrated intensity maps of the whole prominence were obtained from observations in six spectral lines: Ca II H, Hϵ, Hβ, He I D3, Hα, and Ca II IR. By combining integrated intensity maps with non-LTE
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Modeling the thermal conduction in the solar atmosphere with the code MANCHA3D
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Generalized Fluid Models of the Braginskii Type
Several generalizations of the well-known fluid model of Braginskii (1965) are considered. We use the Landau collisional operator and the moment method of Grad. We focus on the 21-moment model that is analogous to the Braginskii model, and we also consider a 22-moment model. Both models are formulated for general multispecies plasmas with arbitrary
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Ambipolar diffusion: Self-similar solutions and MHD code testing. Cylindrical symmetry
Context. Ambipolar diffusion is a process occurring in partially ionised astrophysical systems that imparts a complicated mathematical and physical nature to Ohm's law. The numerical codes that solve the magnetohydrodynamic (MHD) equations have to be able to deal with the singularities that are naturally created in the system by the ambipolar
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Construction of coronal hole and active region magnetohydrostatic solutions in two dimensions: Force and energy balance
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Recent Applications of Bayesian Methods to the Solar Corona
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32022 -
Methodology for Predicting the Probability Distribution of the Amplitude of Solar Cycle 25
A number of precursor-type methods for solar-cycle prediction are based on the use of regression models and confidence-level estimates. A drawback of these methods is that they do not permit one to make probability statements, nor do they offer straightforward ways to propagate the uncertainty from observations to the quantities of interest. We
Arregui, IñigoFecha de publicación:
22022 -
Probing the Physics of the Solar Atmosphere with the Multi-slit Solar Explorer (MUSE). I. Coronal Heating
The Multi-slit Solar Explorer (MUSE) is a proposed mission composed of a multislit extreme ultraviolet (EUV) spectrograph (in three spectral bands around 171 Å, 284 Å, and 108 Å) and an EUV context imager (in two passbands around 195 Å and 304 Å). MUSE will provide unprecedented spectral and imaging diagnostics of the solar corona at high spatial (
De Pontieu, Bart et al.Fecha de publicación:
22022 -
Probing the Physics of the Solar Atmosphere with the Multi-slit Solar Explorer (MUSE). II. Flares and Eruptions
Current state-of-the-art spectrographs cannot resolve the fundamental spatial (subarcseconds) and temporal (less than a few tens of seconds) scales of the coronal dynamics of solar flares and eruptive phenomena. The highest-resolution coronal data to date are based on imaging, which is blind to many of the processes that drive coronal energetics
Cheung, Mark C. M. et al.Fecha de publicación:
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Transverse kink oscillations of inhomogeneous prominence threads: Numerical analysis and Hα forward modelling
Context. Prominence threads are very long and thin flux tubes that are partially filled with cold plasma. Observations have shown that transverse oscillations are frequent in these solar structures. The observations are usually interpreted as the fundamental kink mode, while the detection of the first harmonic remains elusive. Aims: The properties
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22022 -
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Solar surges related to UV bursts. Characterization through k-means, inversions, and density diagnostics
Context. Surges are cool and dense ejections typically observed in chromospheric lines and closely related to other solar phenomena such as UV bursts or coronal jets. Even though surges have been observed for decades now, questions regarding their fundamental physical properties such as temperature and density, as well as their impact on upper
Nóbrega-Siverio, D. et al.Fecha de publicación:
112021 -
Large-amplitude longitudinal oscillations in solar prominences simulated with different resolutions
Context. Large-amplitude longitudinal oscillations (LALOs) in solar prominences have been widely studied in recent decades. However, their damping and amplification mechanisms are not well understood. Aims: In this study, we investigate the attenuation and amplification of LALOs using high-resolution numerical simulations with progressively
Liakh, V. et al.Fecha de publicación:
102021 -
Effect of momentum and heat losses on the hydrodynamic instability of a premixed equidiffusive flame in a Hele-Shaw cell
The linear stage of hydrodynamic instability of a laminar premixed flame propagating in a Hele-Shaw cell is investigated. Our theoretical model takes into account momentum and heat losses, temperature-dependent transport coefficients, and the continuous internal structure of the flame front. The dispersion relation is obtained numerically as a
Han, Yifan et al.Fecha de publicación:
102021 -
Evidence of the multi-thermal nature of spicular downflows. Impact on solar atmospheric heating
Context. Spectroscopic observations of the emission lines formed in the solar transition region commonly show persistent downflows on the order of 10−15 km s−1. The cause of such downflows, however, is still not fully clear and has remained a matter of debate. Aims: We aim to understand the cause of such downflows by studying the coronal and
Bose, Souvik et al.Fecha de publicación:
102021