Magnestismo Solar y Estelar

    General
    Descripción

    Los campos magnéticos son uno de los ingredientes fundamentales en la formación de estrellas y su evolución. En el nacimiento de una estrella, los campos magnéticos llegan a frenar su rotación durante el colapso de la nube molecular, y en el fin de la vida de una estrella, el magnetismo puede ser clave en la forma en la que se pierden las capas externas de forma dramática. En la vida adulta, el magnetismo da lugar a la actividad de las estrellas. Nuestro Sol tiene campos magnéticos que dan lugar a una actividad tan espectacular que es capaz de tener un impacto en la Tierra. Pero en otras estrellas, la actividad magnética es, en algunos casos, órdenes de magnitud más intensa que la solar, influenciando drásticamente el transporte de especies químicas y de momento angular, así como afectando posibles sistemas planetarios alrededor de éstas.

    La finalidad de este Proyecto es estudiar diversas manifestaciones del campo magnético que se pueden observar en la atmosfera solar y en otras estrellas. Estas incluyen estructuras tan diversas como las manchas solares, los campos débiles presentes en el sol en calma o estructuras cromosféricas y coronales como los filamentos y las protuberancias. Así, se han ido abordando gradualmente los siguientes temas de investigación:

     

    Magnetismo solar

    1. Estructura y evolución del campo magnético en manchas solares.
    2. Estructura y evolución del campo magnético en el Sol en calma.
    3. Estructura y evolución del campo magnético en la cromosfera y en estructuras cromosféricas (protuberancias, espículas,...)
    4. Estructura y evolución del campo magnético en bucles coronales.
    5. Estructura y evolución del campo magnético global del Sol. Estudios del ciclo de actividad magnética.
    6. Estudio empírico de la propagación de ondas magnetohidrodinámicas en el seno de estructuras magnéticas.
    7. Estudio empírico de mecanismos relacionados con el calentamiento de las capas externas del Sol.
    8. Estudio empírico de la influencia de la ionización parcial en la dinamica de la atmosfera solar.
    9. Implicación en el proyecto del Telescopio Solar Europeo.

    Magnetismo estelar

    1. Desarrollo de métodos numéricos para el diagnóstico del campo magnético estelar, tanto en la superficie como en la cromosfera.
    2. Estudio del magnetismo en protuberancias estelares.
    3. Impacto del campo magnético en las últimas fases de la evolución estelar.
    Investigador principal
    Personal del proyecto
    1. Ondas espirales en manchas solares: Se han interpretado como ondas magnetoacústicas que se propagan desde el interior hasta capas atmosféricas siguiendo la dirección del campo magnético. Se ha caracterizado la topología del campo magnético de la mancha, descartando que la forma espiral sea consecuencia del retorcimiento de las líneas de campo (Felipe et al. 2019).
    2. Respuesta magnética a umbral flashes: Observaciones espectropolarimétricas simultáneas de las líneas cromosféricas He I 10830 y Ca II 8542 fueron usadas para estimar las fluctuaciones del campo magnético asociado a ondas de choque. Los choques provocan la expansión de las líneas de campo (Houston et al. 2018, incluye a A. Asensio Ramos).

    Publicaciones relacionadas

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      Future ground-based telescopes will expand our capabilities for simultaneous multi-line polarimetric observations in a wide range of wavelengths, from the near-ultraviolet to the near-infrared. This creates a strong demand to compare candidate spectral lines to establish a guideline of the lines that are most appropriate for each observation target

      Quintero Noda, C. et al.

      Fecha de publicación:

      8
      2021
      Número de citas
      6
    • Constraining the magnetic vector in the quiet solar photosphere and the impact of instrumental degradation

      Context. With the advent of next generation high resolution telescopes, our understanding of how the magnetic field is organized in the internetwork (IN) photosphere is likely to advance significantly. Aims: We aim to evaluate the extent to which we can retrieve accurate information about the magnetic vector in the IN photosphere using inversion

      Campbell, R. J. et al.

      Fecha de publicación:

      10
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      Número de citas
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    • Limitations of the Ca II 8542 Å Line for the Determination of Magnetic Field Oscillations

      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, temperature, and, according to several recent works, magnetic field. In this study, we aim to ascertain the accuracy of the magnetic field determined from inversions of

      Felipe, Tobias et al.

      Fecha de publicación:

      9
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    • Performance of solar far-side active region neural detection

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      Broock, E. G. et al.

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      8
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    • Exploring the Sun's upper atmosphere with neural networks: Reversed patterns and the hot wall effect

      We have developed an inversion procedure designed for high-resolution solar spectro-polarimeters, such as those of Hinode and the DKIST. The procedure is based on artificial neural networks trained with profiles generated from random atmospheric stratifications for a high generalization capability. When applied to Hinode data, we find a hot fine

      Socas-Navarro, H. et al.

      Fecha de publicación:

      8
      2021
      Número de citas
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    • Two-fluid simulations of Rayleigh-Taylor instability in a magnetized solar prominence thread. II. Effects of collisionality

      Solar prominences are formed by partially ionized plasma with inter-particle collision frequencies generally warranting magnetohydrodynamic treatment. In this work we explore the dynamical impacts and observable signatures of two-fluid effects in the parameter regimes when ion-neutral collisions do not fully couple the neutral and charged fluids

      Popescu Braileanu, B. et al.

      Fecha de publicación:

      6
      2021
      Número de citas
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    • Bayesian Evidence for a Nonlinear Damping Model for Coronal Loop Oscillations

      Recent observational and theoretical studies indicate that the damping of solar coronal loop oscillations depends on the oscillation amplitude. We consider two mechanisms: linear resonant absorption and a nonlinear damping model. We confront theoretical predictions from these models with observed data in the plane of observables defined by the

      Arregui, Iñigo

      Fecha de publicación:

      7
      2021
      Número de citas
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    • Machine learning initialization to accelerate Stokes profile inversions

      Context. At present, an exponential growth in scientific data from current and upcoming solar observatories is expected. Most of the data consist of high spatial and temporal resolution cubes of Stokes profiles taken in both local thermodynamic equilibrium (LTE) and non-LTE spectral lines. The analysis of such solar observations requires complex

      Gafeira, R. et al.

      Fecha de publicación:

      7
      2021
      Número de citas
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    • Mapping the Hidden Magnetic Field of the Quiet Sun

      The Sun is the only star where we can resolve the intricate magnetism that all convective stars harbor. Yet, more than 99% of its visible surface along the solar cycle (the so-called quiet Sun) is filled with a tangled, unresolved magnetism. These "hidden" fields are thought to store enough magnetic energy to play a role in the heating of the Sun's

      Trelles Arjona, J. C. et al.

      Fecha de publicación:

      7
      2021
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    • Chromospheric Heating by Magnetohydrodynamic Waves and Instabilities

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      Srivastava, A. K. et al.

      Fecha de publicación:

      6
      2021
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    • Simulations of the Biermann battery mechanism in two-fluid partially ionised plasmas

      Context. In the absence of an initial seed, the Biermann battery term of a non-ideal induction equation acts as a source that generates weak magnetic fields. These fields are then amplified via a dynamo mechanism. The Kelvin-Helmholtz instability is a fluid phenomenon that takes place in many astrophysical scenarios and can trigger the action of

      Martínez-Gómez, D. et al.

      Fecha de publicación:

      6
      2021
      Número de citas
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    • Probing Uncertainties in Diagnostics of a Synthetic Chromosphere

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      Schmit, Don et al.

      Fecha de publicación:

      5
      2021
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    • Rubidium abundances in solar metallicity stars

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      Abia, C. et al.

      Fecha de publicación:

      4
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    • Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)

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      Rast, Mark P. et al.

      Fecha de publicación:

      4
      2021
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    • Combining magneto-hydrostatic constraints with Stokes profiles inversions. II. Application to Hinode/SP observations

      Context. Inversion techniques applied to the radiative transfer equation for polarized light are capable of inferring the physical parameters in the solar atmosphere (temperature T, magnetic field B, and line-of-sight velocity vlos) from observations of the Stokes vector (i.e., spectropolarimetric observations) in spectral lines. Inferences are

      Borrero, J. M. et al.

      Fecha de publicación:

      3
      2021
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    • Empirical determination of atomic line parameters of the 1.5 μm spectral region

      Context. Both the quality and amount of astrophysical data are steadily increasing over time owing to the improvement of telescopes and their instruments. This requires corresponding evolution of the techniques used for obtaining and analyzing the resulting data. The infrared spectral range at 1.56 μm usually observed by the GRegor Infrared

      Trelles Arjona, J. C. et al.

      Fecha de publicación:

      4
      2021
      Número de citas
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    • Temporal evolution of small-scale internetwork magnetic fields in the solar photosphere

      Context. While the longitudinal field that dominates in photospheric network regions has been studied extensively, small-scale transverse fields have recently been found to be ubiquitous in the quiet internetwork photosphere and this merits further study. Furthermore, few observations have been able to capture how this field evolves. Aims: We aim

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      3
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      Número de citas
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    • Acoustic-gravity wave propagation characteristics in three-dimensional radiation hydrodynamic simulations of the solar atmosphere

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      2
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    • Magnetoacoustic wave energy dissipation in the atmosphere of solar pores

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      Gilchrist-Millar, Caitlin A. et al.

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      2
      2021
      Número de citas
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    • Influence of ambipolar and Hall effects on vorticity in three-dimensional simulations of magneto-convection

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      Khomenko, E. et al.

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      2
      2021
      Número de citas
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