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- ItemThe European Solar Telescope(Les Ulis : EDP Sciences, 2022) Quintero Noda, C.; Schlichenmaier, R.; Bellot Rubio, L.R.; Löfdahl, M.G.; Khomenko, E.; Jurčák, J.; Leenaarts, J.; Kuckein, C.; González Manrique, S.J.; Gunár, S.; Nelson, C.J.; Giovannelli, L.; González, F.; González, J.B.; González-Cava, J.M.; González García, M.; Gömöry, P.; Gracia, F.; Grauf, B.; Greco, V.; Grivel, C.; de la Cruz Rodríguez, J.; Guerreiro, N.; Guglielmino, S.L.; Hammerschlag, R.; Hanslmeier, A.; Hansteen, V.; Heinzel, P.; Hernández-Delgado, A.; Hernández Suárez, E.; Hidalgo, S.L.; Hill, F.; Tziotziou, K.; Hizberger, J.; Hofmeister, S.; Jägers, A.; Janett, G.; Jarolim, R.; Jess, D.; Jiménez Mejías, D.; Jolissaint, L.; Kamlah, R.; Kapitán, J.; Tsiropoula, G.; Kašparová, J.; Keller, C.U.; Kentischer, T.; Kiselman, D.; Kleint, L.; Klvana, M.; Kontogiannis, I.; Krishnappa, N.; Kučera, A.; Labrosse, N.; Aulanier, G.; Lagg, A.; Landi Degl’Innocenti, E.; Langlois, M.; Lafon, M.; Laforgue, D.; Le Men, C.; Lepori, B.; Lepreti, F.; Lindberg, B.; Lilje, P.B.; Aboudarham, J.; López Ariste, A.; López Fernández, V.A.; López Jiménez, A.C.; López López, R.; Manso Sainz, R.; Marassi, A.; Marco de la Rosa, J.; Marino, J.; Marrero, J.; Martín, A.; Allegri, D.; Martín Gálvez, A.; Martín Hernando, Y.; Masciadri, E.; Martínez González, M.; Matta-Gómez, A.; Mato, A.; Mathioudakis, M.; Matthews, S.; Mein, P.; Merlos García, F.; Alsina Ballester, E.; Moity, J.; Montilla, I.; Molinaro, M.; Molodij, G.; Montoya, L.M.; Munari, M.; Murabito, M.; Núñez Cagigal, M.; Oliviero, M.; Orozco Suárez, D.; Amans, J.P.; Ortiz, A.; Padilla-Hernández, C.; Paéz Mañá, E.; Paletou, F.; Pancorbo, J.; Pastor Cañedo, A.; Pastor Yabar, A.; Peat, A.W.; Pedichini, F.; Peixinho, N.; Asensio Ramos, A.; Peñate, J.; Pérez de Taoro, A.; Peter, H.; Petrovay, K.; Piazzesi, R.; Pietropaolo, E.; Pleier, O.; Poedts, S.; Pötzi, W.; Podladchikova, T.; Bailén, F.J.; Prieto, G.; Quintero Nehrkorn, J.; Ramelli, R.; Ramos Sapena, Y.; Rasilla, J.L.; Reardon, K.; Rebolo, R.; Regalado Olivares, S.; Reyes García-Talavera, M.; Riethmüller, T.L.; Balaguer, M.; Rimmele, T.; Rodríguez Delgado, H.; Rodríguez González, N.; Rodríguez-Losada, J.A.; Rodríguez Ramos, L.F.; Romano, P.; Roth, M.; Rouppe van der Voort, L.; Rudawy, P.; Ruiz de Galarreta, C.; Baldini, V.; Rybák, J.; Salvade, A.; Sánchez-Capuchino, J.; Sánchez Rodríguez, M.L.; Sangiorgi, M.; Sayède, F.; Scharmer, G.; Scheiffelen, T.; Schmidt, W.; Schmieder, B.; Balthasar, H.; Scirè, C.; Scuderi, S.; Siegel, B.; Sigwarth, M.; Simões, P.J.A.; Snik, F.; Sliepen, G.; Sobotka, M.; Socas-Navarro, H.; Sola La Serna, P.; Barata, T.; Solanki, S. K.; Soler Trujillo, M.; Soltau, D.; Sordini, A.; Sosa Méndez, A.; Stangalini, M.; Steiner, O.; Stenflo, J.O.; Štěpán, J.; Strassmeier, K.G.; Barczynski, K.; Sudar, D.; Suematsu, Y.; Sütterlin, P.; Tallon, M.; Temmer, M.; Tenegi, F.; Tritschler, A.; Trujillo Bueno, J.; Turchi, A.; Utz, D.; Barreto Cabrera, M.; van Harten, G.; van Noort, M.; van Werkhoven, T.; Vansintjan, R.; Vaz Cedillo, J.J.; Vega Reyes, N.; Verma, M.; Veronig, A.M.; Viavattene, G.; Vitas, N.; Baur, A.; Vögler, A.; von der Lühe, O.; Volkmer, R.; Waldmann, T.A.; Walton, D.; Wisniewska, A.; Zeman, J.; Zeuner, F.; Zhang, L.Q.; Zuccarello, F.; Béchet, C.; Collados, M.; Beck, C.; Belío-Asín, M.; Bello-González, N.; Belluzzi, L.; Bentley, R.D.; Berdyugina, S.V.; Berghmans, D.; Berlicki, A.; Berrilli, F.; Berkefeld, T.; Bettonvil, F.; Bianda, M.; Bienes Pérez, J.; Bonaque-González, S.; Brajša, R.; Bommier, V.; Bourdin, P.-A.; Burgos Martín, J.; Calchetti, D.; Calcines, A.; Calvo Tovar, J.; Campbell, R.J.; Carballo-Martín, Y.; Carbone, V.; Carlin, E.S.; Carlsson, M.; Castro López, J.; Cavaller, L.; Cavallini, F.; Cauzzi, G.; Cecconi, M.; Chulani, H.M.; Cirami, R.; Consolini, G.; Coretti, I.; Cosentino, R.; Cózar-Castellano, J.; Dalmasse, K.; Danilovic, S.; De Juan Ovelar, M.; Del Moro, D.; del Pino Alemán, T.; del Toro Iniesta, J. C.; Denker, C.; Dhara, S.K.; Di Marcantonio, P.; Díaz Baso, C.J.; Diercke, A.; Dineva, E.; Díaz-García, J.J.; Doerr, H.-P.; Doyle, G.; Erdelyi, R.; Ermolli, I.; Escobar Rodríguez, A.; Esteban Pozuelo, S.; Faurobert, M.; Felipe, T.; Feller, A.; Feijoo Amoedo, N.; Femenía Castellá, B.; Fernandes, J.; Ferro Rodríguez, I.; Figueroa, I.; Fletcher, L.; Franco Ordovas, A.; Gafeira, R.; Gardenghi, R.; Gelly, B.; Giorgi, F.; Gisler, D.The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l'Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems.
- ItemInnovative and automated method for vortex identification(Les Ulis : EDP Sciences, 2022) Canivete Cuissa, J. R.; Steiner, O.Context. As a universally accepted definition of a vortex has not yet been established, the community lacks an unambiguous and rigorous method for identifying vortices in fluid flows. Such a method would be useful for conducting robust statistical studies on vortices in highly dynamical and turbulent systems such as the solar atmosphere. Aims. We aim to develop an innovative and robust automated methodology for the identification of vortices based on local and global characteristics of the flow, while avoiding the use of a threshold that could potentially prevent the detection of weak vortices in the process. Methods. We present a new method that combines the rigor of mathematical criteria with the global perspective of morphological techniques. The core of the method consists of an estimation of the center of rotation for every point of the flow that presents some degree of curvature in its neighborhood. For this purpose, we employed the Rortex criterion and combined it with morphological considerations of the velocity field. We then identified coherent vortical structures based on clusters of estimated centers of rotation. Results. We demonstrate that the Rortex is a more reliable criterion than the swirling strength and the vorticity for the extraction of physical information from vortical flows, because it measures the rigid-body rotational part of the flow alone and is not biased by the presence of pure or intrinsic shears. We show that the method performs well in the context of a simplistic test case composed of two Lamb-Oseen vortices. We combined the proposed method with a state-of-the-art clustering algorithm to build an automated vortex identification algorithm. The algorithm was applied to an artificial flow composed of multiple Lamb- Oseen vortices, with a random noisy background, and to the turbulent flow of a simulated magneto-hydrodynamical Orszag-Tang vortex test. The results demonstrate the reliability and accuracy of the method. Conclusions. The present automated vortex identification method can be considered a new tool for the detection and study of vortices in dynamical and turbulent (magneto)hydrodynamical flows. By applying the implemented algorithm to numerical simulations and observational data, as well as comparing it to existing detection methods, we seek to successively improve the reliability of the detections and, ultimately, our knowledge on swirling motions in the solar, stellar, and planetary atmospheres.
- ItemVortex Motions in the Solar Atmosphere: Definitions, Theory, Observations, and Modelling(Dordrecht [u.a.] : Springer Science + Business Media B.V, 2023) Tziotziou, K.; Scullion, E.; Shelyag, S.; Steiner, O.; Khomenko, E.; Tsiropoula, G.; Canivete Cuissa, J.R.; Wedemeyer, S.; Kontogiannis, I.; Yadav, N.; Kitiashvili, I. N.; Skirvin, S.J.; Dakanalis, I.; Kosovichev, A.G.; Fedun, V.Vortex flows, related to solar convective turbulent dynamics at granular scales and their interplay with magnetic fields within intergranular lanes, occur abundantly on the solar surface and in the atmosphere above. Their presence is revealed in high-resolution and high-cadence solar observations from the ground and from space and with state-of-the-art magnetoconvection simulations. Vortical flows exhibit complex characteristics and dynamics, excite a wide range of different waves, and couple different layers of the solar atmosphere, which facilitates the channeling and transfer of mass, momentum and energy from the solar surface up to the low corona. Here we provide a comprehensive review of documented research and new developments in theory, observations, and modelling of vortices over the past couple of decades after their observational discovery, including recent observations in Hα, innovative detection techniques, diverse hydrostatic modelling of waves and forefront magnetohydrodynamic simulations incorporating effects of a non-ideal plasma. It is the first systematic overview of solar vortex flows at granular scales, a field with a plethora of names for phenomena that exhibit similarities and differences and often interconnect and rely on the same physics. With the advent of the 4-m Daniel K. Inouye Solar Telescope and the forthcoming European Solar Telescope, the ongoing Solar Orbiter mission, and the development of cutting-edge simulations, this review timely addresses the state-of-the-art on vortex flows and outlines both theoretical and observational future research directions.