Solar and Stellar Magnetism

    General
    Description

    Magnetic fields are at the base of star formation and stellar structure and evolution. When stars are born, magnetic fields brake the rotation during the collapse of the mollecular cloud. In the end of the life of a star, magnetic fields can play a key role in the form of the strong winds that lead to the last stages of stellar evolution. During the whole adult life of a star, magnetic fields are the origin of stellar activity. Our Sun has magnetic fields that give rise to such spectacular activity that impacts the climate on Earth. The magnetic activity in other stars is, in some cases, of orders of magnitude more intense than the solar one, influencing – often drastically – the transport of chemical species and angular momentum, as well as affecting the possible planetary systems around them.

    The aim of this project is the study of the diverse manifestations of the magnetic field that can be observed in the solar atmosphere and in other stars. These include distinct structures as sunspots, weak quiet-sun fields or chromospheric and coronal features such as filaments and prominences. The following research topics have been gradually faced:

    Solar magnetism

    1. Structure and evolution of Sunspot magnetic fields.

    2. Structure and evolution of quiet Sun magnetic fields.

    3. Structure and evolution of the magnetism of the chromosphere and of chromospheric strcutures (promiences, spicules,...)

    4. Structure and evolution or coronal loops.

    5. Structure and evolution of the Sun's global field. Studies of the activity cycle.

    6. Empirical study of propagation of magnetohydrodynamic waves in magnetic structures.

    7. Empirical study of energy transfer mechanisms related with the heating of the external atmospheric layers.

    8. Empirical study of the influence of partial ionisation in the dynamics of the solar atmosphere.

    9. Participation in the European Solar Telescope project.

    Stellar magnetism

    1. Development of numerical tools to diagnose stellar magnetic fields, both in the surface and in the chromsphere.

    2. Study of magnetic fields in stellar prominences.

    3. Study of the role of magnetic fields in the late stages of stellar evolution.

    Principal investigator
    Project staff
    1. Spiral waves in sunspots: They have been interpreted as magnetoacoustic waves propagating from the interior to the atmosphere following the direction of the magnetic field. We have characterized the magnetic field topology, dismissing the twist of the field lines as the cause of the spiral shape (Felipe et al. 2019).
    2. Magnetic response to umbral flashes: Simultaneous spectropolarimetric observations of the chromospheric He I 10830 and Ca II 8542 lines have been used to estimate the fluctuations of the magnetic field associated to shock waves. The shocks cause expansion of the magnetic field lines (Houston et al. 2018, including A. Asensio Ramos).

    Related publications

    Estimating the longitudinal magnetic field in the chromosphere of quiet-Sun magnetic concentrations 2023A&A...672A.141E
    Improved High-resolution Fast Imager 2023JATIS...9a5001D
    Wave Conversion, Decay, and Heating in a Partially Ionized Two-fluid Magneto-atmosphere 2023ApJ...946..108C
    An Iterative OLA Method for Inversion of Solar Spectropolarimetric Data. I. Single- and Multiple-variable Inversions of Thermodynamic Quantities 2023ApJ...944..111A
    Exploring Magnetic Loops and Serpentine Fields in the Quiet Sun with the GRIS-IFU 2023ApJ...944..150C
    The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere 2023MNRAS.520.1738H
    Impact of opacity effects on chromospheric oscillations inferred from NLTE inversions 2023A&A...670A.133F
    Solar-cycle and Latitude Variations in the Internetwork Magnetism 2023ApJ...944...95T
    Magnetic field amplification and structure formation by the Rayleigh-Taylor instability 2023A&A...670A..31P
    Vortex Motions in the Solar Atmosphere 2023SSRv..219....1T
    Towards the Identification and Classification of Solar Granulation Structures Using Semantic Segmentation 2022FrASS...9.6632D
    Optical design of an image-slicer integral field unit with two output slits 2022JATIS...8a5002D
    Polarimetric characterization of segmented mirrors 2022ApOpt..61.4908P
    Large Ion-neutral Drift Velocities and Plasma Heating in Partially Ionized Coronal Rain Blobs 2022ApJ...940L..47M
    FarNet-II: An improved solar far-side active region detection method 2022A&A...667A.132B
    Observational and numerical characterization of a recurrent arc-shaped front propagating along a coronal fan 2022A&A...667A..21S
    Ambipolar Diffusion in the Lower Solar Atmosphere: Magnetohydrodynamic Simulations of a Sunspot 2022ApJ...938..154M
    Polarization Accuracy Verification of the Chromospheric LAyer SpectroPolarimeter 2022SoPh..297..135S
    Evidence of a flare ignited above a low-latitude spotted active region in the ultrafast rotator HK Aqr 2022MNRAS.517..744M
    The European Solar Telescope 2022A&A...666A..21Q
    Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines 2022ApJ...936...67R
    First Light of the Integral Field Unit of GRIS on the GREGOR Solar Telescope 2022JAI....1150014D
    Doppler-velocity Drifts Detected in a Solar Prominence 2022ApJ...934...16Z
    Modeling the thermal conduction in the solar atmosphere with the code MANCHA3D 2022A&A...663A..96N
    Comparative study of Shack-Hartmann configurations for atmospheric turbulence reconstructions in solar adaptive optics 2022OptLE.15807157R
    Generalized Fluid Models of the Braginskii Type 2022ApJS..260...26H
    Solar Hα excess during Solar Cycle 24 from full-disk filtergrams of the Chromospheric Telescope 2022A&A...661A.107D
    Construction of coronal hole and active region magnetohydrostatic solutions in two dimensions: Force and energy balance 2022A&A...660A.136T
    DeSIRe: Departure coefficient aided Stokes Inversion based on Response functions 2022A&A...660A..37R
    Accelerating Non-LTE Synthesis and Inversions with Graph Networks 2022ApJ...928..101V
    Enhanced Channel Calibration for the Image Sensor of the TuMag Instrument 2022Senso..22.2078M
    Recent Applications of Bayesian Methods to the Solar Corona
    A modified Milne-Eddington approximation for a qualitative interpretation of chromospheric spectral lines 2022A&A...659A.156D
    Bayesian Stokes inversion with normalizing flows 2022A&A...659A.165D
    Methodology for Predicting the Probability Distribution of the Amplitude of Solar Cycle 25 2022SoPh..297...21A
    Approximate Bayesian neural Doppler imaging 2022A&A...658A.162A
    Transverse kink oscillations of inhomogeneous prominence threads: Numerical analysis and Hα forward modelling 2022A&A...658A.106M
    Editorial Appreciation 2022SoPh..297...11A
    Observational evidence for two-component distributions describing solar magnetic bright points 2022A&A...657A..79B
    Inference of electric currents in the solar photosphere 2021A&A...656L..20P

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