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Electric field-driven Rayleigh-Taylor-like instability in binary complex plasma

Priya Deshwal, Hitendra K. Malik

TL;DR

The paper investigates Rayleigh-Taylor-like instabilities in a binary complex plasma under an external electric field, focusing on a configuration where a heavier dust layer sits above a lighter one while both species share the same charge-to-mass ratio. It develops analytical dispersion relations for weakly and strongly coupled regimes using linearized dust-fluid theory and the Generalized Hydrodynamics model, and validates them with 2D Langevin MD simulations in LAMMPS. Key findings show the instability growth rate increases with the driving field $E_0$, density gradients, and reduced screening, while strong coupling introduces viscoelastic effects that can modify growth; MD results agree with theory and reproduce interfacial mixing. The work provides a parametric map of RT-like instability in binary dusty plasmas and a framework for interpreting experiments in strongly coupled regimes.

Abstract

This study uses two-dimensional molecular dynamics simulations to explore Rayleigh-Taylor-like instability in a strongly coupled binary complex plasma, when heavier dust particles are positioned above the lighter ones, having the same charge-to-mass ratio, in a planar configuration. Langevin dynamics simulations are used to study the evolution of perturbations at the interface between these two distinct species of charged dust particles, subject to an externally applied electric field and an equilibrium charge density gradient. We have performed analytical calculations to determine the growth rate of instability under both strongly coupled and weakly coupled dusty plasma regimes. These theoretical predictions are subsequently validated through molecular dynamics simulations, enabling the reproduction of the instability in a strongly coupled binary complex plasma. The instability in these cases ultimately causes mixing among the charged species. The study comprehensively analyzes the growth rate as a function of various system parameters, and it offers deeper insight into the underlying physical mechanisms.

Electric field-driven Rayleigh-Taylor-like instability in binary complex plasma

TL;DR

The paper investigates Rayleigh-Taylor-like instabilities in a binary complex plasma under an external electric field, focusing on a configuration where a heavier dust layer sits above a lighter one while both species share the same charge-to-mass ratio. It develops analytical dispersion relations for weakly and strongly coupled regimes using linearized dust-fluid theory and the Generalized Hydrodynamics model, and validates them with 2D Langevin MD simulations in LAMMPS. Key findings show the instability growth rate increases with the driving field , density gradients, and reduced screening, while strong coupling introduces viscoelastic effects that can modify growth; MD results agree with theory and reproduce interfacial mixing. The work provides a parametric map of RT-like instability in binary dusty plasmas and a framework for interpreting experiments in strongly coupled regimes.

Abstract

This study uses two-dimensional molecular dynamics simulations to explore Rayleigh-Taylor-like instability in a strongly coupled binary complex plasma, when heavier dust particles are positioned above the lighter ones, having the same charge-to-mass ratio, in a planar configuration. Langevin dynamics simulations are used to study the evolution of perturbations at the interface between these two distinct species of charged dust particles, subject to an externally applied electric field and an equilibrium charge density gradient. We have performed analytical calculations to determine the growth rate of instability under both strongly coupled and weakly coupled dusty plasma regimes. These theoretical predictions are subsequently validated through molecular dynamics simulations, enabling the reproduction of the instability in a strongly coupled binary complex plasma. The instability in these cases ultimately causes mixing among the charged species. The study comprehensively analyzes the growth rate as a function of various system parameters, and it offers deeper insight into the underlying physical mechanisms.
Paper Structure (7 sections, 29 equations, 9 figures)

This paper contains 7 sections, 29 equations, 9 figures.

Table of Contents

  1. Introduction
  2. Analytical results for electric field-driven RT-like instability in complex plasma
  3. In weak coupling regime
  4. In strong coupling regime using the generalized hydrodynamics model
  5. MD Simulation Details
  6. Results and discussion
  7. Summary

Figures (9)

  • Figure 1: Variation of growth rate with wave number on changing various parameters. Each subplot examines the impact of one parameter while holding all other variables constant. Different colors within a single subplot visually represent the influence of adjusting a particular parameter.
  • Figure 2: Variation of growth rate with wave number on changing charge density while keeping all parameters constant ($\rho_{c0}$).
  • Figure 3: Variation of growth rate with wave number on changing various parameters. Each subplot examines the impact of one parameter while holding all other variables constant. Different colors within a single subplot visually represent the influence of adjusting a particular parameter.
  • Figure 4: Initial configuration of particles in the simulation box.
  • Figure 5: Time evolution of the trajectory of two particles in the simulation box.
  • ...and 4 more figures