A strong diffusive ion mode in dense ionized matter predicted by Langevin dynamics

Area of Science:

• Plasma Physics
• Astrophysics
• Condensed Matter Physics

Background:

• The properties of dense and compressed matter govern the evolution of planets, brown dwarfs, and neutron star crusts.
• Current models of strongly coupled plasmas yield transport coefficients that vary significantly due to modeling complexities.
• Collective modes in dense matter offer a potential method for validating theoretical predictions.

Purpose of the Study:

• To numerically predict low-frequency ion modes in dense matter.
• To investigate the impact of dissipative processes on these ion modes.
• To assess the consequences for interpreting transport coefficients in dense plasmas.

Main Methods:

• Numerical simulations of dense matter.
• Inclusion of dissipative processes using Langevin dynamics.
• Analysis of collective ion mode spectra.

Main Results:

• Dissipative processes significantly alter the strength and dispersion of ion modes.
• A strong diffusive mode near zero frequency emerges when Langevin dynamics are applied.
• This diffusive mode is absent or considerably weaker in standard simulations.

Conclusions:

• Dissipative effects are critical for accurately modeling collective modes in dense plasmas.
• The inclusion of Langevin dynamics provides a more realistic representation of ion behavior.
• These findings necessitate a re-evaluation of transport coefficient interpretations in dense astrophysical objects.