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Related papers: Thermal-Diffusional Instability in White Dwarf Fla…

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We study the nucleation and growth of flame fronts in slow combustion. This is modeled by a set of reaction-diffusion equations for the temperature field, coupled to a background of reactants and augmented by a term describing random…

Statistical Mechanics · Physics 2015-06-25 Mikko Karttunen , Nikolas Provatas , Tapio Ala-Nissila , Martin Grant

We explore the effects of element diffusion due to gravitational settling and thermal and chemical diffusion on the pulsational properties of DA white dwarfs. To this end, we employ an updated evolutionary code coupled with a pulsational,…

Astrophysics · Physics 2009-11-07 A. H. Corsico , O. G. Benvenuto , L. G. Althaus , A. M. Serenelli

Although the evolution of premixed flames in turbulence has been frequently studied, it is not well understood how small flames interact with large-scale turbulent flow motion. Since this question is of practical importance for the…

Fluid Dynamics · Physics 2020-02-04 Tobias Falkenstein , Seongwon Kang , Heinz Pitsch

This paper presents a flame-height correlation for laminar to transition-to-turbulent regime diffusion flames. Flame-height measurements are obtained by means of numerical and experimental studies in which three high definition cameras were…

Several important mechanisms that explain the coherent pulsar radio emission rely on streaming (or beam) instabilities of the relativistic pair plasma in a pulsar magnetosphere. However, it is still not clear whether a streaming instability…

High Energy Astrophysical Phenomena · Physics 2021-06-02 Alina C. Manthei , Jan Benáček , Patricio A. Muñoz , Jörg Büchner

Low mass white dwarfs are the remnants of disrupted red giant stars in binary millisecond pulsars and other exotic binary star systems. Some low mass white dwarfs cool rapidly, while others stay bright for millions of years due to stable…

We consider the behavior of matter in the accretion column that emerges under accretion in binary systems near the surface of a white dwarf. The plasma heated in a standing shock wave near the white dwarf surface efficiently radiates in the…

High Energy Astrophysical Phenomena · Physics 2013-12-18 Andrey Semena , Mikhail Revnivtsev

We study various combinations of active diffusion with branching, as an extension of standard reaction-diffusion processes. We concentrate on the selection of the asymptotic wavefront speed for thermal run-and-tumble and for thermal active…

Statistical Mechanics · Physics 2020-05-22 Thibaut Demaerel , Christian Maes

This work is dedicated to the analysis of the delicate details of the effect of upstream velocity fluctuations on the flame propagation speed. The investigation was carried out using the Sivashinsky model of cellularisation of…

Fluid Dynamics · Physics 2013-05-29 V. Karlin

We present a study of numerical behavior of a thickened flame used in Flame Capturing (FC, Khokhlov (1995)) for tracking thin unresolved physical flames in deflagration simulations. We develop a steady-state procedure for calibrating the…

High Energy Astrophysical Phenomena · Physics 2009-06-03 Andrey V. Zhiglo

We present the first radiation magnetohydrodynamics simulations of the atmosphere of white dwarf stars. We demonstrate that convective energy transfer is seriously impeded by magnetic fields when the plasma-beta parameter, the thermal to…

Solar and Stellar Astrophysics · Physics 2015-10-14 P. -E. Tremblay , G. Fontaine , B. Freytag , O. Steiner , H. -G. Ludwig , M. Steffen , S. Wedemeyer , P. Brassard

Due to a new global analysis method, it is now possible to measure the internal composition of pulsating white dwarf stars, even with relatively simple theoretical models. The precise internal mixture of carbon and oxygen is the largest…

Astrophysics · Physics 2009-11-07 Travis S. Metcalfe

Particle dynamics are investigated in plasma turbulence, using self-consistent kinetic simulations, in two dimensions. In steady state, the trajectories of single protons and proton-pairs are studied, at different values of plasma "beta"…

Plasma Physics · Physics 2016-08-31 S. Servidio , C. T. Haynes , W. H. Matthaeus , D. Burgess , V. Carbone , P. Veltri

Annular chambers, consisting of multiple flame nozzles, are frequently used in many industrial processes, for example, rocket engines and gas turbines. In the study, we proposed a novel approach to the problem of annular combustion with…

Fluid Dynamics · Physics 2025-03-04 Tao Yang , Yuan Ma , Peng Zhang

This work discusses the role of diffusive enthalpy transport in relation to the origin of thermodiffusive instability and the resulting enhanced reactivity. Thermodiffusive effects in premixed hydrogen flames are typically explained and…

Fluid Dynamics · Physics 2025-04-08 Thomas L. Howarth , Terence Lehmann , Michael Gauding , Heinz Pitsch

We study the dynamics of thermonuclear flames propagating in fuel stirred by stochastic forcing. The fuel consists of carbon and oxygen in a state which is encountered in white dwarfs close to the Chandrasekhar limit. The level set method…

Astrophysics · Physics 2015-06-24 W. Schmidt , W. Hillebrandt , J. C. Niemeyer

Reliable modeling of the atmospheres of cool white dwarfs is crucial for understanding the atmospheric evolution of these stars and for accurate white dwarfs cosmochronology. Over the last decade {\it ab initio} modeling entered many…

Solar and Stellar Astrophysics · Physics 2015-05-20 Piotr M. Kowalski

White Dwarf luminosities are powerful age indicators, whose calibration should be based on reliable models. We discuss the uncertainty of some chemical and physical parameters and their influence on the age estimated by means of white dwarf…

Astrophysics · Physics 2009-11-07 P. G. Prada Moroni , O. Straniero

We study the thermodynamics of helium at densities relevant for white dwarf physics. We find evidence that, as the temperature is increased, there is first a first order transition between two superconducting phases followed by a second…

High Energy Astrophysical Phenomena · Physics 2014-02-26 Paulo F. Bedaque , Evan Berkowitz , Srimoyee Sen

The possible existence of warm ($T_{\rm eff}\sim19\,000$ K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. However, to date, no pulsating warm DA WD has been…