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

    • Solar Surface and Atmospheric Dynamics. The Photosphere
      Various aspects of the magnetism of the quiet sun are reviewed. The suggestion that a small scale dynamo acting at granular scales generates what we call the quiet sun fields is studied in some detail. Although dynamo action has been proved numerically, it is argued that current simulations are still far from achieving the complexity that might be
      Martínez-Pillet, V.

      Fecha de publicación:

      10
      2013
      Número de citas
      35
    • MuSICa: The Multi-Slit Image Slicer for the EST Spectrograph
      Integral field spectroscopy (IFS) is a technique that allows one to obtain the spectra of all the points of a bidimensional field of view simultaneously. It is being applied to the new generation of the largest night-time telescopes but it is also an innovative technique for solar physics. This paper presents the design of a new image slicer
      Calcines, A. et al.

      Fecha de publicación:

      9
      2013
      Número de citas
      19
    • Propagating Waves Transverse to the Magnetic Field in a Solar Prominence
      We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb
      Schmieder, B. et al.

      Fecha de publicación:

      11
      2013
      Número de citas
      60
    • A High Resolution Integral Field Spectrograph for the European Solar Telescope
      This paper presents the proposal of a high resolution, integral field spectrograph that is currently being designed for the 4-meter aperture European Solar Telescope that will be located in the Canary Islands. This instrument is optimized to study the solar chromosphere and photosphere to allow the investigation of several phenomena concentrated
      Calcines, A. et al.

      Fecha de publicación:

      6
      2013
      Número de citas
      4
    • Temporal relation between quiet-Sun transverse fields and the strong flows detected by IMaX/SUNRISE
      Context. Localized strongly Doppler-shifted Stokes V signals were detected by IMaX/SUNRISE. These signals are related to newly emerged magnetic loops that are observed as linear polarization features. Aims: We aim to set constraints on the physical nature and causes of these highly Doppler-shifted signals. In particular, the temporal relation
      Quintero Noda, C. et al.

      Fecha de publicación:

      10
      2013
      Número de citas
      14
    • Thermodynamic fluctuations in solar photospheric three-dimensional convection simulations and observations
      Context. Numerical three-dimensional (3D) radiative (magneto-)hydrodynamical [(M)HD] simulations of solar convection are nowadays used to understand the physical properties of the solar photosphere and convective envelope, and, in particular, to determine the Sun's photospheric chemical abundances. To validate this approach, it is important to
      Beck, C. et al.

      Fecha de publicación:

      9
      2013
      Número de citas
      18
    • Can spicules be detected at disc centre in broad-band Ca ii H filter imaging data?
      Context. Recently, a possible identification of type II spicules in broad-band (full-width at half-maximum (FWHM) of ~0.3 nm) filter imaging data in Ca ii H on the solar disc was reported. Aims: We estimate the formation height range contributing to broad-band and narrow-band filter imaging data in Ca ii H to investigate whether spicules can be
      Beck, C. et al.

      Fecha de publicación:

      8
      2013
      Número de citas
      14
    • Dislocations in Magnetohydrodynamic Waves in a Stellar Atmosphere
      We describe the presence of wave front dislocations in magnetohydrodynamic waves in stratified stellar atmospheres. Scalar dislocations such as edges and vortices can appear in Alfvén waves, as well as in general magnetoacoustic waves. We detect those dislocations in observations of magnetohydrodynamic waves in sunspots in the solar chromosphere
      López Ariste, A. et al.

      Fecha de publicación:

      8
      2013
      Número de citas
      10
    • First evidence of interaction between longitudinal and transverse waves in solar magnetic elements
      Small-scale magnetic fields are thought to play an important role in the heating of the outer solar atmosphere. By taking advantage of the unprecedented high-spatial and temporal cadence of the Imaging Magnetograph eXperiment (IMaX), the filter vector polarimeter on board the Sunrise balloon-borne observatory, we study the transversal and
      Stangalini, M. et al.

      Fecha de publicación:

      6
      2013
      Número de citas
      26
    • Coronal loop physical parameters from the analysis of multiple observed transverse oscillations
      The analysis of quickly damped transverse oscillations of solar coronal loops using magneto-hydrodynamic seismology allows us to infer physical parameters that are difficult to measure otherwise. Under the assumption that such damped oscillations are due to the resonant conversion of global modes into Alfvén oscillations of the tube surface, we
      Asensio-Ramos, A. et al.

      Fecha de publicación:

      6
      2013
      Número de citas
      18
    • Determination of Transverse Density Structuring from Propagating Magnetohydrodynamic Waves in the Solar Atmosphere
      We present a Bayesian seismology inversion technique for propagating magnetohydrodynamic transverse waves observed in coronal waveguides. The technique uses theoretical predictions for the spatial damping of propagating kink waves in transversely inhomogeneous coronal waveguides. It combines wave amplitude damping length scales along the waveguide
      Arregui, I. et al.

      Fecha de publicación:

      6
      2013
      Número de citas
      26
    • Atmosphere Dynamics of the Active Region NOAA 11024
      We present results of the study of chromospheric and photospheric line-of-sight velocity fields in the young active region NOAA 11024. Multi-layer, multi-wavelength observational data were used for the analysis of the emerging flux in this active region. Spectropolarimetric observations were carried out with the telescope THEMIS on Tenerife (Canary
      Khomenko, E. V. et al.

      Fecha de publicación:

      6
      2013
      Número de citas
      16
    • The energy of waves in the photosphere and lower chromosphere. IV. Inversion results of Ca II H spectra
      Context. Most semi-empirical static one-dimensional (1D) models of the solar atmosphere in the magnetically quiet Sun (QS) predict an increase in temperature at chromospheric layers. Numerical simulations of the solar chromosphere with a variable degree of sophistication, i.e. from 1D to three-dimensional (3D) simulations; assuming local thermal
      Beck, C. et al.

      Fecha de publicación:

      5
      2013
      Número de citas
      25
    • Is Magnetic Reconnection the Cause of Supersonic Upflows in Granular Cells?
      In a previous work, we reported on the discovery of supersonic magnetic upflows on granular cells in data from the SUNRISE/IMaX instrument. In the present work, we investigate the physical origin of these events employing data from the same instrument but with higher spectral sampling. By means of the inversion of Stokes profiles we are able to
      Borrero, J. M. et al.

      Fecha de publicación:

      5
      2013
      Número de citas
      21
    • Evolution of the Fine Structure of Magnetic Fields in the Quiet Sun: Observations from Sunrise/IMaX and Extrapolations
      Observations with the balloon-borne Sunrise/ Imaging Magnetograph eXperiment (IMaX) provide high spatial resolution (roughly 100 km at disk center) measurements of the magnetic field in the photosphere of the quiet Sun. To investigate the magnetic structure of the chromosphere and corona, we extrapolate these photospheric measurements into the
      Knölker, M. et al.

      Fecha de publicación:

      4
      2013
      Número de citas
      24
    • Effect of partial ionization on wave propagation in solar magnetic flux tubes
      Observations show that waves are ubiquitous in the solar atmosphere and may play an important role for plasma heating. The study of waves in the solar corona is usually based on linear ideal magnetohydrodynamics (MHD) for a fully ionized plasma. However, the plasma in the photosphere and the chromosphere is only partially ionized. Here we
      Goossens, M. et al.

      Fecha de publicación:

      3
      2013
      Número de citas
      20
    • Bayesian Analysis of Multiple Harmonic Oscillations in the Solar Corona
      The detection of multiple mode harmonic kink oscillations in coronal loops enables us to obtain information on coronal density stratification and magnetic field expansion using seismology inversion techniques. The inference is based on the measurement of the period ratio between the fundamental mode and the first overtone and theoretical results
      Díaz, A. J. et al.

      Fecha de publicación:

      3
      2013
      Número de citas
      20
    • Polarisation and magnetic fields in cool stars and the Sun. A session in memory of Meir Semel
      Astrophysical plasmas and magnetic fields are inextricably coupled to each other. But magnetic fields are elusive; they cannot be fully characterized with standard (spectroscopic) observational techniques. Fortunately, polarisation, the third fundamental property of light, encodes all the quantitative information on the magnetism of the objects we
      Marsden, S. C. et al.

      Fecha de publicación:

      2
      2013
      Número de citas
      0
    • The energy of waves in the photosphere and lower chromosphere. III. Inversion setup for Ca II H spectra in local thermal equilibrium
      Context. The Ca II H line is one of the strongest lines in the solar spectrum, and it provides continuous information on the solar atmosphere from the photosphere to the lower chromosphere. Aims: We describe an inversion approach that reproduces observed Ca II H spectra by assuming local thermal equilibrium (LTE). Methods: We developed an inversion
      Puschmann, K. G. et al.

      Fecha de publicación:

      1
      2013
      Número de citas
      24
    • Structure and dynamics of isolated internetwork Ca II H bright points observed by SUNRISE
      Aims: We aim to improve our picture of the low chromosphere in the quiet-Sun internetwork by investigating the intensity, horizontal velocity, size and lifetime variations of small bright points (BPs; diameter smaller than 0.3 arcsec) observed in the Ca ii H 3968 Å passband along with their magnetic field parameters, derived from photospheric
      Martínez-Pillet, V. et al.

      Fecha de publicación:

      1
      2013
      Número de citas
      54

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