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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CMAG: A Mission to Study and Monitor the Inner Corona Magnetic FieldMeasuring magnetic fields in the inner corona, the interface between the solar chromosphere and outer corona, is of paramount importance if we aim to understand the energetic transformations taking place there, and because it is at the origin of processes that lead to coronal heating, solar wind acceleration, and of most of the phenomena relevantOrozco Suárez, David et al.
Advertised on:
112023 -
Tomographic Reconstruction of the Solar K-Corona Using Neural FieldsWe explore the application of neural fields for tomographic reconstructions of the solar corona using data from the Large Angle and Spectrometric Coronagraph (LASCO)-C2 instrument. We first demonstrate their ability to recover the electron-density volume in a synthetic static case, utilizing a simulated 3D model of the corona. Our results show thatAsensio Ramos, Andrés
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112023 -
Comparative Analysis of Image-shift Measurement Algorithms for Solar Shack-Hartmann Wavefront SensorsObservations of the Sun provide unique insights into its structure, evolution, and activity, with significant implications for space weather forecasting and solar energy technologies. Ground-based telescopes offer cost-effective and flexible solutions for high-resolution solar observations, but image quality can be affected by atmosphericWei, Xiya et al.
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112023 -
High-speed data processing onboard sunrise chromospheric infrared spectropolarimeter for the SUNRISE III balloon telescopeThe Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) has been developed for the third flight of the SUNRISE balloon-borne stratospheric solar observatory. The aim of the SCIP is to reveal the evolution of three-dimensional magnetic fields in the solar photosphere and chromosphere using spectropolarimetric measurements with a polarimetricKubo, Masahito et al.
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72023 -
On the Magnetic Nature of Quiet-Sun Chromospheric GrainsCa II K grains, i.e., intermittent, short-lived (about 1 minute), periodic (2-4 minutes), pointlike chromospheric brightenings, are considered to be the manifestations of acoustic waves propagating upward from the solar surface and developing into shocks in the chromosphere. After the simulations of Carlsson and Stein, we know that hot shocked gasMartínez González, María Jesús et al.
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102023 -
Large Photospheric Doppler Shift in Solar Active Region 12673. I. Field-aligned FlowsDelta (δ) sunspots sometimes host fast photospheric flows along the central magnetic polarity inversion line (PIL). Here we study the strong Doppler shift signature in the central penumbral light bridge of solar active region NOAA 12673. Observations from the Helioseismic and Magnetic Imager (HMI) indicate highly sheared and strong magnetic fieldsLiu, Jiayi et al.
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92023 -
Bayesian evidence for two slow-wave damping models in hot coronal loopsWe computed the evidence in favour of two models, one based on field-aligned thermal conduction alone and another that includes thermal misbalance as well, to explain the damping of slow magneto-acoustic waves in hot coronal loops. Our analysis is based on the computation of the marginal likelihood and the Bayes factor for the two damping modelsArregui, I. et al.
Advertised on:
82023 -
Magnetic field fluctuations in the shocked umbral chromosphereContext. Umbral chromospheric observations show the presence of magnetoacoustic shocks. Several recent studies have reported magnetic field fluctuations associated with these shock waves. The mechanism behind these periodic magnetic field changes is still an unresolved question. Aims: We aim to study the properties and origin of magnetic fieldFelipe, T. et al.
Advertised on:
82023 -
Machine learning in solar physicsThe application of machine learning in solar physics has the potential to greatly enhance our understanding of the complex processes that take place in the atmosphere of the Sun. By using techniques such as deep learning, we are now in the position to analyze large amounts of data from solar observations and identify patterns and trends that mayAsensio Ramos, Andrés et al.
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122023 -
Transverse oscillations and an energy source in a strongly magnetized sunspotThe solar corona is two to three orders of magnitude hotter than the underlying photosphere, and the energy loss of coronal plasma is extremely strong, requiring a heating flux of over 1,000 W m −2 to maintain its high temperature. Using the 1.6 m Goode Solar Telescope, we report a detection of ubiquitous and persistent transverse waves in umbralYuan, Ding et al.
Advertised on:
72023 -
Accelerating Multiframe Blind Deconvolution via Deep LearningGround-based solar-image restoration is a computationally expensive procedure that involves nonlinear optimization techniques. The presence of atmospheric turbulence produces perturbations in individual images that make it necessary to apply blind deconvolution techniques. These techniques rely on the observation of many short-exposure frames thatAsensio Ramos, Andrés et al.
Advertised on:
72023 -
iNNterpol: High-precision interpolation of stellar atmospheres with a deep neural network using a 1D convolutional auto encoder for feature extractionContext. Given the widespread availability of grids of models for stellar atmospheres, it is necessary to recover intermediate atmospheric models by means of accurate techniques that go beyond simple linear interpolation and capture the intricacies of the data. Aims: Our goal is to establish a reliable, precise, lightweight, and fast method forWestendorp Plaza, C. et al.
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72023 -
Opacity for realistic 3D MHD simulations of cool stellar atmospheresContext. Realistic three-dimensional time-dependent simulations of stellar near-surface convection employ the opacity binning method for the efficient and accurate computation of the radiative energy exchange. The method provides several orders of magnitude of speedup, but its implementation includes a number of free parameters. Aims: Our aim is toPerdomo García, A. et al.
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72023 -
A study of the capabilities for inferring atmospheric information from high-spatial-resolution simulationsIn this work, we study the accuracy that can be achieved when inferring the atmospheric information from realistic numerical magneto-hydrodynamic simulations that reproduce the spatial resolution we will obtain with future observations made by the 4m class telescopes DKIST and EST. We first study multiple inversion configurations using the SIR codeQuintero Noda, C. et al.
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72023 -
Synthesis of infrared Stokes spectra in an evolving solar chromospheric jetChromospheric jets are plausible agents of energy and mass transport in the solar chromosphere, although their driving mechanisms have not yet been elucidated. Magnetic field measurements are key for distinguishing the driving mechanisms of chromospheric jets. We performed a full Stokes synthesis in the infrared range with a realistic radiativeMatsumoto, T. et al.
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72023 -
Numerical simulations of prominence oscillations triggered by external perturbationsContext. Several energetic disturbances have been identified as triggers of large-amplitude oscillations (LAOs) in prominences. Observations show that Moreton or extreme ultraviolet waves excite prominence oscillations of the longitudinal, transverse, or mixed polarities. However, the mechanisms for the excitation of LAOs by these waves are notLiakh, V. et al.
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52023 -
The role of the chromospheric magnetic canopy in the formation of a sunspot penumbraContext. While it is conjectured that a chromospheric canopy plays a role in penumbra formation, it has been difficult to find observational evidence of the connectivity between the photosphere and the chromosphere. Aims: We investigate the existence of a chromospheric canopy as a necessary condition for the formation of a penumbra. Another aim isLindner, P. et al.
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52023 -
Estimating the longitudinal magnetic field in the chromosphere of quiet-Sun magnetic concentrationsContext. Details of the magnetic field in the quiet-Sun chromosphere are key to our understanding of essential aspects of the solar atmosphere. However, the strength and orientation of this magnetic field have not been thoroughly studied at high spatial resolution. Aims: We aim to determine the longitudinal magnetic field component (B ∥) of quietEsteban Pozuelo, S. et al.
Advertised on:
42023 -
Improved High-resolution Fast ImagerThe improved High-resolution Fast Imager (HiFI+) is a multiwavelength imaging filtergraph, which was commissioned at the GREGOR solar telescope at Observatorio del Teide, Izaña, Tenerife, Spain, in March 2022 - followed by science verification in April 2022, after which it entered routine observations. Three camera control computers with twoDenker, Carsten et al.
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12023 -
Wave Conversion, Decay, and Heating in a Partially Ionized Two-fluid Magneto-atmosphereA ray-theoretic phase-space description of linear waves in a two-fluid (charges and neutrals) magnetized plasma is used to calculate analytic decay rates and mode transmission and conversion coefficients between fast and slow waves in two dimensions due to finite ion-neutral collision frequencies at an arbitrary ionization fraction. This isCally, Paul S. et al.
Advertised on:
42023
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