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.

2020, Abbasvand, V., Sobotka, M., Švanda, M., Heinzel, P., García-Rivas, M., Denker, C., Balthasar, H., Verma, M., Kontogiannis, I., Koza, J., Korda, D., Kuckein, C.

Aims. Our aim is to investigate the role of acoustic and magneto-acoustic waves in heating the solar chromosphere. Observations in strong chromospheric lines are analyzed by comparing the deposited acoustic-energy flux with the total integrated radiative losses. Methods. Quiet-Sun and weak-plage regions were observed in the Ca ii 854.2 nm and H lines with the Fast Imaging Solar Spectrograph (FISS) at the 1.6-m Goode Solar Telescope on 2019 October 3 and in the H and H lines with the echelle spectrograph attached to the Vacuum Tower Telescope on 2018 December 11 and 2019 June 6. The deposited acoustic energy flux at frequencies up to 20 mHz was derived from Doppler velocities observed in line centers and wings. Radiative losses were computed by means of a set of scaled non-local thermodynamic equilibrium 1D hydrostatic semi-empirical models obtained by fitting synthetic to observed line profiles. Results. In the middle chromosphere (h = 1000–1400 km), the radiative losses can be fully balanced by the deposited acoustic energy flux in a quiet-Sun region. In the upper chromosphere (h > 1400 km), the deposited acoustic flux is small compared to the radiative losses in quiet as well as in plage regions. The crucial parameter determining the amount of deposited acoustic flux is the gas density at a given height. Conclusions. The acoustic energy flux is e ciently deposited in the middle chromosphere, where the density of gas is su ciently high. About 90% of the available acoustic energy flux in the quiet-Sun region is deposited in these layers, and thus it is a major contributor to the radiative losses of the middle chromosphere. In the upper chromosphere, the deposited acoustic flux is too low, so that other heating mechanisms have to act to balance the radiative cooling.

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.