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Magnetic activity changes the gravito-acoustic modes of solar-like stars and in particular their frequencies. There is an angular-degree dependence that is believed to be caused by the non-spherical nature of the magnetic activity in the…

Solar and Stellar Astrophysics · Physics 2019-06-26 F. Perez Hernandez , R. A. Garcia , S. Mathur , A. R. G. Santos , C. Regulo

In Hezaveh et al. 2017 we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational lensing systems. Here we demonstrate a method for…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-29 Laurence Perreault Levasseur , Yashar D. Hezaveh , Risa H. Wechsler

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations, and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive…

Solar and Stellar Astrophysics · Physics 2015-06-15 Regner Trampedach , Martin Asplund , Remo Collet , Åke Nordlund , Robert F. Stein

Since the prediction of climate is mainly considered as a prediction of second kind, it is indispensable to assess the accuracy with which these boundary conditions can be determined so that we can find a reasonable answer, whether climate…

Atmospheric and Oceanic Physics · Physics 2009-11-13 Gerhard Kramm , Ralph Dlugi

Machine learning has emerged as a promising approach for estimating material parameters in solar cells. Traditional methods for parameter extraction often rely on time-consuming numerical simulations that fail to capture the full complexity…

Materials Science · Physics 2025-06-17 Eunchi Kim , Paula Hartnagel , Barbara Urbano , Leonard Christen , Thomas Kirchartz

Determining the magnetic field of solar spicules is vital for developing adequate models of these plasma jets, which are thought to play a key role in the thermal, dynamic, and magnetic structure of the chromosphere. Here we report on…

Solar and Stellar Astrophysics · Physics 2015-05-13 R. Centeno , J. Trujillo Bueno , A. Asensio Ramos

Lightning plays a crucial role in the Earth's climate system, yet existing parameterizations for use in forecasting and earth system models show room for improvement in capturing spatial and temporal variations in its frequency. This study…

Atmospheric and Oceanic Physics · Physics 2025-09-15 Randall Jones , Joel A. Thornton , Chris J. Wright , Robert Holzworth

Small scale magnetic fields can be observed on the Sun in G-band filtergrams as MBPs (magnetic bright points) or identified in spectro-polarimetric measurements due to enhanced signals of Stokes profiles. These magnetic fields and their…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. Utz , J. Jurčák , A. Hanslmeier , R. Muller , A. Veronig , O. Kühner

The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energetic stellar phenomena such as flares and coronal mass…

Solar and Stellar Astrophysics · Physics 2023-07-26 Prantika Bhowmik , Jie Jiang , Lisa Upton , Alexandre Lemerle , Dibyendu Nandy

Magnetic fields are one of the most important drivers of the highly dynamic processes that occur in the lower solar atmosphere. They span a broad range of sizes, from large- and intermediate-scale structures such as sunspots, pores and…

Solar and Stellar Astrophysics · Physics 2015-03-13 Stefan Thonhofer , Luis R. Bellot Rubio , Dominik Utz , Arnold Hanslmeier , Jan Jurčák

Inferring magnetic and thermodynamic information from spectropolarimetric observations relies on the assumption of a parameterized model atmosphere whose parameters are tuned by comparison with observations. Often, the choice of the…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. Asensio Ramos , R. Manso Sainz , M. J. Martinez Gonzalez , B. Viticchie , D. Orozco Suarez , H. Socas-Navarro

Context: Sunspot penumbrae harbor highly structured magnetic fields and flows. The moving flux tube model offers an explanation for several observed phenomena, e.g. the Evershed effect and bright penumbral grains. Aims: A wealth of…

Astrophysics · Physics 2007-05-23 D. A. N. Mueller , R. Schlichenmaier , G. Fritz , C. Beck

A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are > $10^9$ photometrically cataloged sources, yet modern spectroscopic surveys are limited to ~few x $10^6$ targets. As we…

Solar and Stellar Astrophysics · Physics 2015-06-23 A. A. Miller , J. S. Bloom , J. W. Richards , Y. S. Lee , D. L. Starr , N. R. Butler , S. Tokarz , N. Smith , J. A. Eisner

The major challenges for a fully polarized radiative transfer driven approach to Zeeman-Doppler imaging are still the enormous computational requirements. In every cycle of the iterative interplay between the forward process (spectral…

Astrophysics · Physics 2008-07-25 T. A. Carroll , M. Kopf , K. G. Strassmeier

In the past, spectropolarimetric data from Hinode/SP has been employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors have found predominantly horizontal magnetic fields, others favor an…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. M. Borrero , P. Kobel

Machine Learning has become a pervasive tool in climate science applications. However, current models fail to address nonstationarity induced by anthropogenic alterations in greenhouse emissions and do not routinely quantify the uncertainty…

Machine Learning · Computer Science 2024-02-22 Simon Dräger , Maike Sonnewald

We propose a forecasting approach for solar flares based on data from Solar Cycle 24, taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) mission. In particular, we use the Space-weather HMI…

Inversion codes allow reconstructing a model atmosphere from observations. With the inclusion of optically thick lines that form in the solar chromosphere, such modelling is computationally very expensive because a non-LTE evaluation of the…

Solar and Stellar Astrophysics · Physics 2019-04-19 Alberto Sainz Dalda , Jaime de la Cruz Rodríguez , Bart De Pontieu , Milan Gošić

We present the first interpretation of the Stokes profile asymmetries measured in the FeI 630 nm lines by SOT/SP, in both quiet Sun internetwork (IN) and network regions. The inversion is carried out under the hypothesis of MISMA, where the…

Solar and Stellar Astrophysics · Physics 2015-05-20 B. Viticchié , J. , Sánchez Almeida , D. Del Moro , F. Berrilli

The Mg II k resonance line is commonly used for diagnosing the solar chromosphere. We theoretically investigated its intensity and polarization in solar prominences, taking 3D radiative transfer and Hanle and Zeeman effects into account. We…

Solar and Stellar Astrophysics · Physics 2024-09-25 Jiří Štěpán , Tanausú del Pino Alemán , Javier Trujillo Bueno