Start year
1999
Organizational Unit
Organizing institutions
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.
Members
Principal investigator
Tobías
Felipe García
Project staff
Elena
Khomenko Shchukina
Íñigo
Arregui Uribe-Echevarría
Andrés
Asensio Ramos
Carlos Humberto
Domínguez-Tagle Paredes
María Jesús
Martínez González
Juan Carlos
Trelles Arjona
Carlos
Westendorp Plaza
Collaborators
Héctor David
Socas Navarro
Dr.
J.C. del Toro Iniesta
Dr.
R. Kostik
Dr.
N. Shchukina
Dr.
V. Olshevsky
Dr.
A. Sainz Dalda
Dr.
W. Schmidt
Dr.
Th. Berkefeld
Dr.
S.K. Solanki
Dr.
A. Gandorfer
Prof.
P. Cally
Dr.
S. Shelyag
Dr.
M. Stangalini
Dr.
C. Beck
Dr.
C. Kuckein
Dr.
C. Quintero Noda
Dr.
I. Calvo Santamaria
Dr.
C. González Fernández
Dr.
J.de la Cruz Rodríguez
Dr.
M. Leitzinger
Dr.
A. Pastor Yabar
Dr.
A. López Ariste
Dr.
Franco Leone
Dr.
R. Manso Sainz
Dr.
Luis R Bellot Rubio
Results
- 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).
- 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).
Scientific activity
Related publications
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Solar Surface and Atmospheric Dynamics. The PhotosphereVarious 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 beMartínez-Pillet, V.
Advertised on:
102013 -
MuSICa: The Multi-Slit Image Slicer for the EST SpectrographIntegral 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 slicerCalcines, A. et al.
Advertised on:
92013 -
Propagating Waves Transverse to the Magnetic Field in a Solar ProminenceWe 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 barbSchmieder, B. et al.
Advertised on:
112013 -
A High Resolution Integral Field Spectrograph for the European Solar TelescopeThis 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 concentratedCalcines, A. et al.
Advertised on:
62013 -
Temporal relation between quiet-Sun transverse fields and the strong flows detected by IMaX/SUNRISEContext. 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 relationQuintero Noda, C. et al.
Advertised on:
102013 -
Thermodynamic fluctuations in solar photospheric three-dimensional convection simulations and observationsContext. 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 toBeck, C. et al.
Advertised on:
92013 -
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 beBeck, C. et al.
Advertised on:
82013 -
Dislocations in Magnetohydrodynamic Waves in a Stellar AtmosphereWe 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 chromosphereLópez Ariste, A. et al.
Advertised on:
82013 -
First evidence of interaction between longitudinal and transverse waves in solar magnetic elementsSmall-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 andStangalini, M. et al.
Advertised on:
62013 -
Coronal loop physical parameters from the analysis of multiple observed transverse oscillationsThe 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, weAsensio-Ramos, A. et al.
Advertised on:
62013 -
Determination of Transverse Density Structuring from Propagating Magnetohydrodynamic Waves in the Solar AtmosphereWe 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 waveguideArregui, I. et al.
Advertised on:
62013 -
Atmosphere Dynamics of the Active Region NOAA 11024We 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 (CanaryKhomenko, E. V. et al.
Advertised on:
62013 -
The energy of waves in the photosphere and lower chromosphere. IV. Inversion results of Ca II H spectraContext. 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 thermalBeck, C. et al.
Advertised on:
52013 -
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 toBorrero, J. M. et al.
Advertised on:
52013 -
Evolution of the Fine Structure of Magnetic Fields in the Quiet Sun: Observations from Sunrise/IMaX and ExtrapolationsObservations 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 theKnölker, M. et al.
Advertised on:
42013 -
Effect of partial ionization on wave propagation in solar magnetic flux tubesObservations 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 weGoossens, M. et al.
Advertised on:
32013 -
Bayesian Analysis of Multiple Harmonic Oscillations in the Solar CoronaThe 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 resultsDíaz, A. J. et al.
Advertised on:
32013 -
Polarisation and magnetic fields in cool stars and the Sun. A session in memory of Meir SemelAstrophysical 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 weMarsden, S. C. et al.
Advertised on:
22013 -
The energy of waves in the photosphere and lower chromosphere. III. Inversion setup for Ca II H spectra in local thermal equilibriumContext. 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 inversionPuschmann, K. G. et al.
Advertised on:
12013 -
Structure and dynamics of isolated internetwork Ca II H bright points observed by SUNRISEAims: 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 photosphericMartínez-Pillet, V. et al.
Advertised on:
12013
