Subvenciones relacionadas:
General
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
- Estructura y evolución del campo magnético en manchas solares.
- Estructura y evolución del campo magnético en el Sol en calma.
- Estructura y evolución del campo magnético en la cromosfera y en estructuras cromosféricas (protuberancias, espículas,...)
- Estructura y evolución del campo magnético en bucles coronales.
- Estructura y evolución del campo magnético global del Sol. Estudios del ciclo de actividad magnética.
- Estudio empírico de la propagación de ondas magnetohidrodinámicas en el seno de estructuras magnéticas.
- Estudio empírico de mecanismos relacionados con el calentamiento de las capas externas del Sol.
- Estudio empírico de la influencia de la ionización parcial en la dinamica de la atmosfera solar.
- Implicación en el proyecto del Telescopio Solar Europeo.
Magnetismo estelar
- Desarrollo de métodos numéricos para el diagnóstico del campo magnético estelar, tanto en la superficie como en la cromosfera.
- Estudio del magnetismo en protuberancias estelares.
- Impacto del campo magnético en las últimas fases de la evolución estelar.
Miembros
Resultados
- 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).
- 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).
Actividad científica
Publicaciones relacionadas
-
Modeling the thermal conduction in the solar atmosphere with the code MANCHA3DContext. Thermal conductivity is one of the important mechanisms of heat transfer in the solar corona. In the limit of strongly magnetized plasma, it is typically modeled by Spitzer's expression where the heat flux is aligned with the magnetic field. Aims: This paper describes the implementation of the heat conduction into the code MANCHA3D with anNavarro, A. et al.
Fecha de publicación:
72022 -
Comparative study of Shack-Hartmann configurations for atmospheric turbulence reconstructions in solar adaptive opticsThe correction of the phase variations induced by the atmospheric turbulence is one of the most complex problems that an Adaptive Optics (AO) System must deal with, as it must calculate the properties of all the atmosphere traversed by the light from several measures taken by ground-based telescopes. Traditional reconstructors systems used in AORiesgo, Francisco García et al.
Fecha de publicación:
112022 -
Generalized Fluid Models of the Braginskii TypeSeveral 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 arbitraryHunana, P. et al.
Fecha de publicación:
62022 -
Solar Hα excess during Solar Cycle 24 from full-disk filtergrams of the Chromospheric TelescopeContext. The chromospheric Hα spectral line is a strong line in the spectrum of the Sun and other stars. In the stellar regime, this spectral line is already used as a powerful tracer of stellar activity. For the Sun, other tracers, such as Ca II K, are typically used to monitor solar activity. Nonetheless, the Sun is observed constantly in Hα withDiercke, A. et al.
Fecha de publicación:
52022 -
Construction of coronal hole and active region magnetohydrostatic solutions in two dimensions: Force and energy balanceCoronal holes and active regions are typical magnetic structures found in the solar atmosphere. We propose several magnetohydrostatic equilibrium solutions that are representative of these structures in two dimensions. Our models include the effect of a finite plasma-β and gravity, but the distinctive feature is that we incorporate a thermalTerradas, J. et al.
Fecha de publicación:
42022 -
DeSIRe: Departure coefficient aided Stokes Inversion based on Response functionsFuture ground-based telescopes, such as the 4-metre class facilities DKIST and EST, will dramatically improve on current capabilities for simultaneous multi-line polarimetric observations in a wide range of wavelength bands, from the near-ultraviolet to the near-infrared. As a result, there will be an increasing demand for fast diagnostic tools, iRuiz Cobo, B. et al.
Fecha de publicación:
42022 -
Accelerating Non-LTE Synthesis and Inversions with Graph NetworksThe computational cost of fast non-LTE synthesis is one of the challenges that limits the development of 2D and 3D inversion codes. It also makes the interpretation of observations of lines formed in the chromosphere and transition region a slow and computationally costly process, which limits the inference of the physical properties on ratherVicente Arévalo, A. et al.
Fecha de publicación:
42022 -
Enhanced Channel Calibration for the Image Sensor of the TuMag InstrumentThe Sunrise missions consist of observing the magnetic field of the sun continuously for a few days from the stratosphere. In these missions, a balloon supporting a telescope and associated instrumentation, including a Tunable Magnetograph (TuMag), is lifted into the stratosphere. In the camera of this instrument, the image sensor sends its data toMagdaleno, Eduardo et al.
Fecha de publicación:
32022 -
Recent Applications of Bayesian Methods to the Solar CoronaSolar coronal seismology is based on the remote diagnostics of physical conditions in the corona of the Sun by comparison between model predictions and observations of magnetohydrodynamic wave activity. Our lack of direct access to the physical systems of interest makes information incomplete and uncertain so our conclusions are at bestArregui, I.
Fecha de publicación:
32022 -
A modified Milne-Eddington approximation for a qualitative interpretation of chromospheric spectral linesContext. The Milne-Eddington approximation provides an analytic and simple solution to the radiative transfer equation. It can be easily implemented in inversion codes used to fit spectro-polarimetric observations and infer average values of the magnetic field vector and the line-of-sight velocity of the solar plasma. However, in principle, it isDorantes-Monteagudo, A. J. et al.
Fecha de publicación:
32022 -
Bayesian Stokes inversion with normalizing flowsStokes inversion techniques are very powerful methods for obtaining information on the thermodynamic and magnetic properties of solar and stellar atmospheres. In recent years, highly sophisticated inversion codes have been developed that are now routinely applied to spectro-polarimetric observations. Most of these inversion codes are designed toDíaz Baso, C. J. et al.
Fecha de publicación:
32022 -
Methodology for Predicting the Probability Distribution of the Amplitude of Solar Cycle 25A 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. WeArregui, Iñigo
Fecha de publicación:
22022 -
Approximate Bayesian neural Doppler imagingAims: The non-uniform surface temperature distribution of rotating active stars is routinely mapped with the Doppler imaging technique. Inhomogeneities in the surface produce features in high-resolution spectroscopic observations that shift in wavelength because of the Doppler effect, depending on their position on the visible hemisphere. TheAsensio Ramos, A. et al.
Fecha de publicación:
22022 -
Transverse kink oscillations of inhomogeneous prominence threads: Numerical analysis and Hα forward modellingContext. 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 propertiesMartínez-Gómez, David et al.
Fecha de publicación:
22022 -
-
Observational evidence for two-component distributions describing solar magnetic bright pointsContext. High-resolution observations of the solar photosphere reveal the presence of fine structures, in particular the so-called Magnetic Bright Points (MBPs), which are small-scale features associated with strong magnetic field regions of the order of kilogauss (kG). It is especially relevant to study these magnetic elements, which areBerrios Saavedra, Gerardine et al.
Fecha de publicación:
12022 -
Inference of electric currents in the solar photosphereContext. Despite their importance, routine and direct measurements of electric currents, j, in the solar atmosphere have generally not been possible. Aims: We aim at demonstrating the capabilities of a newly developed method for determining electric currents in the solar photosphere. Methods: We employ three-dimensional radiative magnetoPastor Yabar, A. et al.
Fecha de publicación:
122021 -
Measurements of Photospheric and Chromospheric Magnetic Field Structures Associated with Chromospheric Heating over a Solar Plage RegionIn order to investigate the relation between magnetic structures and the signatures of heating in plage regions, we observed a plage region with the He I 1083.0 nm and Si I 1082.7 nm lines on 2018 October 3 using the integral field unit mode of the GREGOR Infrared Spectrograph (GRIS) installed at the GREGOR telescope. During the GRIS observationAnan, Tetsu et al.
Fecha de publicación:
112021 -
Multiple Stokes I inversions for inferring magnetic fields in the spectral range around Cr I 5782 ÅAims: In this work, we explore 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 Å, with Landé g-factors between 1.6 and 2.5. The goal is to simultaneously analyze 15 spectral lines, comprising Cr I, Cu I, Fe I, Mn I, and Si IKuckein, C. et al.
Fecha de publicación:
92021 -
Large-amplitude longitudinal oscillations in solar prominences simulated with different resolutionsContext. 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 progressivelyLiakh, V. et al.
Fecha de publicación:
102021