Electron Screening Effect on Stellar Thermonuclear Fusion

Potekhin, A. Y.; Chabrier, G.

doi:10.1002/ctpp.201200094

Cited by 18 publications

(15 citation statements)

References 39 publications

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“…However, the electron mass is important at the lower densities in WDs and this may change our results slightly [32]. Also quantum effects could play some role at high densities [33,34].…”

Section: A MD Formalismmentioning

confidence: 70%

Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas

et al. 2012

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We determine the liquid-solid phase diagram for carbon-oxygen and oxygen-selenium plasma mixtures using two-phase molecular dynamics simulations. We identify liquid, solid, and interface regions using a bond angle metric. To study finite-size effects, we perform 27 648-and 55 296-ion simulations. To help monitor nonequilibrium effects, we calculate diffusion constants D i . For the carbon-oxygen system we find that D O for oxygen ions in the solid is much smaller than D C for carbon ions and that both diffusion constants are 80 or more times smaller than diffusion constants in the liquid phase. There is excellent agreement between our carbon-oxygen phase diagram and that predicted by Medin and Cumming. This suggests that errors from finite-size and nonequilibrium effects are small and that the carbon-oxygen phase diagram is now accurately known. The oxygen-selenium system is a simple two-component model for more complex rapid proton capture nucleosynthesis ash compositions for an accreting neutron star. Diffusion of oxygen, in a predominantly selenium crystal, is remarkably fast, comparable to diffusion in the liquid phase. We find a somewhat lower melting temperature for the oxygen-selenium system than that predicted by Medin and Cumming. This is probably because of electron screening effects.

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“…However, the electron mass is important at the lower densities in WDs and this may change our results slightly [32]. Also quantum effects could play some role at high densities [33,34].…”

Section: A MD Formalismmentioning

confidence: 70%

Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas

et al. 2012

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“…As long as the electron screening can be viewed as static, this reduces to a modification of the inter-ion potential. However, it is not straightforward, because such a potential should not be described by the simple Thomas-Fermi screening model (Potekhin & Chabrier 2013). A more realistic electron dielectric function and potential would have to be used which may significantly slow down the simulations.…”

Section: Discussionmentioning

confidence: 99%

“…Effectively, other ions push the pair of fusing nuclei towards each other forcing them to be closer and to spend more time near each other thereby enhancing the tunneling probability (e.g., Ogata 1997). On top of that, the electron density responds to the presence of nuclei and screens the Coulomb force between them (e.g., Potekhin & Chabrier 2013). Thus, the ambient plasma results in a reduction of the Coulomb barrier and an amplification of the reaction rates.…”

Section: Introductionmentioning

confidence: 99%

Plasma screening of nuclear fusion reactions in liquid layers of compact degenerate stars: a first-principle study

Baiko

2021

Preprint

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A reliable description of nuclear fusion reactions in inner layers of white dwarfs and envelopes of neutron stars is important for realistic modelling of a wide range of observable astrophysical phenomena from accreting neutron stars to type Ia supernovae. We study the problem of screening of the Coulomb barrier impeding the reactions, by a plasma surrounding the fusing nuclei. Numerical calculations of the screening factor are performed from the first principles with the aid of quantum-mechanical path integrals in the model of a one-component plasma of atomic nuclei for temperatures and densities typical for dense liquid layers of compact degenerate stars. We do not rely on various quasiclassic approximations widely used in the literature, such as factoring-out the tunneling process, tunneling in an average spherically symmetric mean-force potential, usage of classic free energies and pair correlation functions, linear mixing rule and so on. In general, a good agreement with earlier results from the thermonuclear limit to Γ ∼ 100 is found. For a very strongly coupled liquid 100 Γ 175, a deviation from currently used parametrisations of the reaction rates is discovered and approximated by a simple analytic expression. The developed method of nuclear reaction rate calculations with account of plasma screening can be extended to ion mixtures and crystallised phases of stellar matter.

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“…The state of the art of the electron screening in nuclear fusions in stars has been summarized by Chabrier and Potekhin [48,49]. In addition, Dappen-Mussak [36,37] and Shaviv [50] have criticized the use of the stationary Salpeter screening.…”

Section: Validity Of the Ideal Plasma Model: Comments And Requirementsmentioning

confidence: 99%

Negentropy in Many-Body Quantum Systems

Quarati

Lissia

Scarfone

2016

Entropy

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Negentropy (negative entropy) is the negative contribution to the total entropy of correlated many-body environments. Negentropy can play a role in transferring its related stored mobilizable energy to colliding nuclei that participate in spontaneous or induced nuclear fusions in solid or liquid metals or in stellar plasmas. This energy transfer mechanism can explain the observed increase of nuclear fusion rates relative to the standard Salpeter screening. The importance of negentropy in these specific many-body quantum systems and its relation to many-body correlation entropy are discussed.

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Electron Screening Effect on Stellar Thermonuclear Fusion

Cited by 18 publications

References 39 publications

Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas

Direct molecular dynamics simulation of liquid-solid phase equilibria for two-component plasmas

Plasma screening of nuclear fusion reactions in liquid layers of compact degenerate stars: a first-principle study

Negentropy in Many-Body Quantum Systems

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