Nuclear Reaction Screening, Weak Interactions, and r-Process Nucleosynthesis in High Magnetic Fields

Abstract

Coulomb screening and weak interactions in a hot, magnetized plasma are investigated. Coulomb screening is evaluated in a relativistic thermal plasma in which electrons and positrons are in equilibrium. In addition to temperature effects, effects on weak screening from a strong external magnetic field are evaluated. In high fields, the electron transverse momentum components are quantized into Landau levels. The characteristic plasma screening length at high temperatures and at high magnetic fields is explored. In addition to changes to the screening length, changes in weak interaction rates are estimated. It is found that high fields can result in increased $\beta$-decay rates as the electron and positron spectra are dominated by Landau levels. Finally, the effects studied here are evaluated in a simple r-process model. It is found that relativistic Coulomb screening has a small effect on the final abundance distribution. While changes in weak interaction rates in strong magnetic fields can have an effect on the r-process evolution and abundance distribution, the field strength required to have a significant effect may be larger than what is currently thought to be typical of the r-process environment in collapsar jets or neutron star mergers. If r-process sites exist in fields $\gtrsim 10^{14}$ G effects from fields on weak decays could be significant.

24 pages, 16 figures

References in corpus (16)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Pulsational Pair-Instability Supernovae
• Producing ultra-strong magnetic fields in neutron star mergers
• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Very massive stars, pair-instability supernovae and intermediate-mass black holes with the SEVN code
• High resolution numerical-relativity simulations for the merger of binary magnetized neutron stars
• Special Relativistic Simulations of Magnetically-dominated Jets in Collapsing Massive Stars
• Fast evolving pair-instability supernova models: evolution, explosion, light curves
• Updated constraint on a primordial magnetic field during big bang nucleosynthesis and a formulation of field effects
• Fission Cycling in a Supernova r-process
• Long-Term Evolution of Slowly Rotating Collapsar in Special Relativistic Magnetohydrodynamics
• Modified Debye-Huckel Electron Shielding and Penetration Factor
• Electron screening and its effects on Big-Bang nucleosynthesis
• Electron fraction constraints based on Nuclear Statistical Equilibrium with beta equilibrium
• Plasma-screening effects in the atrophysically relevant He-like and Li-like Mg and Fe ions
• Determination of plasma screening effects for thermonuclear reactions in laser-generated plasmas