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Enhanced chromospheric emission which corresponds to an outwardly increasing semiempirical temperature structure can be produced by wave motion without any increase in the mean gas temperture. Hence, the sun may not have a classical…

Astrophysics · Physics 2009-10-22 Mats Carlsson , Robert F. Stein

The question how the outer solar atmosphere is heated from solar photospheric temperatures of about 5800K up to solar chromospheric and coronal temperatures of about 20.000K and millions of degrees respectively, remained without any…

General Physics · Physics 2020-05-13 Klaus Gerhard Puschmann

We elucidate the interplay between Newtonian thermal relaxation and numerical dissipation, of several different origins, in flow simulations of hot extrasolar planet atmospheres. Currently, a large range of Newtonian relaxation, or…

Earth and Planetary Astrophysics · Physics 2010-10-27 Heidar Thor Thrastarson , James Y-K. Cho

We consider the effects of the heat balance on the structural stability of a preflare current layer. The problem of small perturbations is solved in the piecewise homogeneous MHD approximation taking into account the viscosity, the…

Solar and Stellar Astrophysics · Physics 2021-04-30 Leonid Ledentsov

Within the framework of a two-fluid description possible pathways for the generation of fast flows (dynamical as well as steady) in the lower solar atmosphere is established. It is shown that a primary plasma flow (locally sub-Alfv\'enic)…

How do magnetohydrodynamic waves travel from the fully ionized corona, into and through the underlying partially ionized chromosphere, and what are the consequences for solar flares? To address these questions, we have developed a 2-fluid…

Solar and Stellar Astrophysics · Physics 2013-02-22 Alexander J. B. Russell , Lyndsay Fletcher

Recent experiments claimed that the enhancement of catalytic reaction rates occurs via the reduction of activation barriers driven by non-equilibrium (``hot'') electrons in plasmonic metal nanoparticles. These experiments place plasmonic…

Chemical Physics · Physics 2020-04-22 Yonatan Sivan , Ieng Wai Un , Yonatan Dubi

The connection between nuclear fusion in the Sun's core and solar irradiance is obscured among other things by uncertainty over the mechanism of coronal heating. Data for solar wind density and velocity, sunspot number, and EUV flux suggest…

Solar and Stellar Astrophysics · Physics 2016-09-16 Claudio Vita-Finzi

We proposed that the use of an approximate "jump condition" at the solar transition region permits fast and accurate numerical solutions of the one dimensional hydrodynamic equations when the corona undergoes impulsive heating. In…

Solar and Stellar Astrophysics · Physics 2017-08-30 C. D. Johnston , A. W. Hood , P. J. Cargill , I. De Moortel

We present a new global model of the solar corona, including the low corona, the transition region and the top of chromosphere. The realistic 3D magnetic field is simulated using the data from the photospheric magnetic field measurements.…

Although thermal pressure is unimportant dynamically in most molecular gas, the temperature is an important diagnostic of dynamical processes and physical conditions. This is the first of two papers on thermal equilibrium in molecular…

Astrophysics · Physics 2009-10-31 Paolo Padoan , ; Ellen Zweibel , ; AAke Nordlund

We performed numerical simulations to study mechanisms of solar prominence formation triggered by a single heating event. In the widely accepted ``chromospheric-evaporation condensation" model, localized heating at footpoints of a coronal…

Solar and Stellar Astrophysics · Physics 2024-11-28 Takero Yoshihisa , Takaaki Yokoyama , Takafumi Kaneko

The relationship between a decaying strong turbulence and kinetic instabilities in a slowly expanding plasma is investigated using two-dimensional (2-D) hybrid expanding box simulations. We impose an initial ambient magnetic field…

We have performed a 2.5 dimensional magnetohydrodynamic simulation that resolves the propagation and dissipation of Alfven waves in the solar atmosphere. Alfvenic fluctuations are introduced on the bottom boundary of the extremely large…

Solar and Stellar Astrophysics · Physics 2015-06-18 Takuma Matsumoto , Takeru K. Suzuki

We present an efficient heating/cooling method coupled with chemistry and ultraviolet (UV) radiative transfer, which can be applied to numerical simulations of the interstellar medium (ISM). We follow the time-dependent evolution of…

Astrophysics of Galaxies · Physics 2022-12-28 Jeong-Gyu Kim , Munan Gong , Chang-Goo Kim , Eve C. Ostriker

For experiments that require a quantum system to be in the ultra-cold regime, laser cooling is an essential tool. While techniques for laser cooling ions and neutral atoms have been refined and temperatures below the Doppler limit have been…

Atomic Physics · Physics 2024-10-31 Caleb Heuvel-Horwitz , S. F. Yelin

We consider the atmospheric flow on short-period extra-solar planets through two-dimensional numerical simulations of hydrodynamics with radiation transfer. One side is always exposed to the irradiation from the host star. The other is…

Astrophysics · Physics 2014-10-13 Andreas Burkert , Douglas Lin , Peter Bodenheimer , Chris Jones , Harold Yorke

Stratification due to ion-ion friction in a magnetized multiple-ion species plasma is shown to be accompanied by a heat pump effect, identified for the first time here, transferring heat from one ion species to another as well as from one…

Plasma Physics · Physics 2020-08-05 M. E. Mlodik , E. J. Kolmes , I. E. Ochs , N. J. Fisch

Molecular dynamics simulations are used to model ion and neutral temperature evolution in partially-ionized atmospheric pressure plasma at different ionization fractions. Results show that ion-ion interactions are strongly coupled at…

Plasma Physics · Physics 2023-01-04 M. D. Acciarri , C. Moore , S. D. Baalrud

Context. The solar chromosphere is the interface between the solar surface and the solar corona. Modelling of this region is difficult because it represents the transition from optically thick to thin radiation escape, from gas-pressure…

Solar and Stellar Astrophysics · Physics 2015-12-09 Mats Carlsson , Viggo H. Hansteen , Boris V. Gudiksen , Jorrit Leenaarts , Bart De Pontieu
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