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Analyses of a 3D simulation of the upper layers of a solar convective envelope provide constraints on the physical quantities which enter the theoretical formulation of a stochastic excitation model of solar p modes, for instance the…

Astrophysics · Physics 2009-11-07 R. Samadi , A. Nordlund , R. F. Stein , M. J. Goupil , I. Roxburgh

The form of the solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. Yet a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic…

Solar and Stellar Astrophysics · Physics 2015-02-17 Dario Passos , Paul Charbonneau , Mark Miesch

Identifying the heating mechanisms of the solar corona and the driving mechanisms of solar wind are key challenges in understanding solar physics. A full three-dimensional compressible magnetohydrodynamic (MHD) simulation was conducted to…

Solar and Stellar Astrophysics · Physics 2020-11-25 Takuma Matsumoto

Numerical 3D radiative (M)HD simulations of solar convection are used to understand the physical properties of the solar photosphere. To validate this approach, it is important to check that no excessive thermodynamic fluctuations arise as…

Solar and Stellar Astrophysics · Physics 2015-06-16 C. Beck , D. Fabbian , F. Moreno-Insertis , K. G. Puschmann , R. Rezaei

We present comparison of numerical simulations of propagation of MHD waves,excited by subphotospheric perturbations, in two different ("deep" and "shallow") magnetostatic models of the sunspots. The "deep" sunspot model distorts both the…

Solar and Stellar Astrophysics · Physics 2016-09-08 K. Parchevsky , A. Kosovichev , E. Khomenko , V. Olshevsky , M. Collados

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magneto-acoustic…

Solar and Stellar Astrophysics · Physics 2017-02-01 G. Vigeesh , J. Jackiewicz , O. Steiner

Recent models of variations of the Sun's structure with the 11-year activity cycle by Sofia et al (2005) predict strong non-homologous changes of the radius of subsurface layers, due to subsurface magnetic fields and field-modulated…

Astrophysics · Physics 2009-11-13 S. Lefebvre , A. G. Kosovichev , J. P. Rozelot

Mutual conversion of various kinds of magnetohydrodynamic (MHD) waves can have profound impacts on wave propagation, energy transfer, and heating of the solar chromosphere and corona. Mode conversion occurs when an MHD wave travels through…

Solar and Stellar Astrophysics · Physics 2024-04-01 Pankaj Kumar , Valery M. Nakariakov , Judith T. Karpen , Kyung-Suk Cho

Artificially increasing the luminosity and the thermal diffusivity of a model is a common tactic adopted in hydrodynamical simulations of stellar convection. In this work, we analyse the impact of these artificial modifications on the…

Solar and Stellar Astrophysics · Physics 2022-04-20 A. Le Saux , T. Guillet , I. Baraffe , D. G. Vlaykov , T. Constantino , J. Pratt , T. Goffrey , M. Sylvain , V. Réville , A. S. Brun

Magnetic cycles of solar-like stars influence their internal physics. Thus, the frequency, amplitude, excitation rate, and damping of the acoustic oscillation modes (p-modes) vary with the cycle over time. We need to understand the impact…

Solar and Stellar Astrophysics · Physics 2024-11-08 E. Panetier , S. N. Breton , R. A. García , A. Jiménez , T. Foglizzo

Long-term trends in the solar spectral irradiance are important to determine the impact on Earth's climate. These long-term changes are thought to be caused mainly by changes in the surface area covered by small-scale magnetic elements. The…

Solar and Stellar Astrophysics · Physics 2015-05-14 N. Afram , Y. C. Unruh , S. K. Solanki , M. Schuessler , S. K. Mathew

Aims. In this paper we analyse numerically the propagation and dispersion of acoustic waves in the solar-like sub-photosphere with localised non-uniform magnetic field concentrations, mimicking sunspots with various representative magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Shelyag , S. Zharkov , V. Fedun , R. Erdelyi , M. J. Thompson

Numerical MHD simulations of 3D reconnection events in the solar corona have improved enormously over the last few years, not only in resolution, but also in their complexity, enabling more and more realistic modeling. Various ways to…

Solar and Stellar Astrophysics · Physics 2012-11-07 G. Baumann , K. Galsgaard , Å. Nordlund

Solar magnetic activity follows regular cycles of about 11 years with an inversion of polarity in the poles every 22 years. This changing surface magnetism impacts the properties of the acoustic modes. The acoustic mode frequency shifts are…

Solar and Stellar Astrophysics · Physics 2024-11-27 Rafael A. Garcia , Sylvain N. Breton , David Salabert , Sushant C. Tripathy , Kiran Jain , Savita Mathur , Eva Panetier

An overview is given about recent developments and results of comprehensive simulations of magneto-convective processes in the near-surface layers and photosphere of the Sun. Simulations now cover a wide range of phenomena, from whole…

Solar and Stellar Astrophysics · Physics 2015-06-12 Manfred Schüssler

We extend semi-analytical computations of excitation rates for solar oscillation modes to those of other solar-like oscillating stars to compare them with recent observations. Numerical 3D simulations of surface convective zones of several…

Astrophysics · Physics 2009-11-11 R. Samadi , D. Georgobiani , R. Trampedach R. , M. -J. Goupil , R. F. Stein , A. Nordlund

Context. Tracing wave activity from the photosphere to the corona has important implications for coronal heating and prediction of the solar wind. Despite extensive theory and simulations, the detection of waves in realistic MHD simulations…

Solar and Stellar Astrophysics · Physics 2025-08-28 George Cherry , Boris Gudiksen , Adam J. Finley

While it has been relatively easy to determine solar-cycle related changes in solar dynamics, determining changes in structure in the deeper layers of the Sun has proved to be difficult. By using helioseismic data obtained over two solar…

Solar and Stellar Astrophysics · Physics 2021-08-25 Sarbani Basu

We present a comprehensive radiative magnetohydrodynamic simulation of the quiet Sun and large solar active regions. The 197 Mm wide simulation domain spans from 18 (10) Mm beneath the photosphere to 113 Mm in the solar corona. Radiative…

Solar and Stellar Astrophysics · Physics 2022-10-12 Feng Chen , Matthias Rempel , Yuhong Fan

The questions whether the Sun shrinks with the solar activity and what causes this have been a subject of debate. Helioseismology provides means to measure with high precision the radial displacement of subsurface layers, co-called "seismic…

Solar and Stellar Astrophysics · Physics 2018-07-25 Alexander Kosovichev , Jean-Pierre Rozelot