Dynamic response of two‐component model plasmas

Zwicknagel, G.; Pschiwul, T.

doi:10.1002/ctpp.200310054

Cited by 16 publications

(14 citation statements)

References 13 publications

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“…2). The similar interaction model was used, e.g., in [18][19][20] for simulations of ionized metallic clusters. More accurate electron-ion and electron-electron interaction models are discussed, e.g., in [21,22] although they seem to be redundant for this particular case.…”

Section: Simulation Techniquementioning

confidence: 99%

Sheath parameters for non-Debye plasmas: Simulations and arc damage

Морозов

Norman

Insepov

et al. 2012

Phys. Rev. ST Accel. Beams

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This paper describes the surface environment of the dense plasma arcs that damage rf accelerators, tokamaks, and other high gradient structures. We simulate the dense, nonideal plasma sheath near a metallic surface using molecular dynamics (MD) to evaluate sheaths in the non-Debye region for high density, low temperature plasmas. We use direct two-component MD simulations where the interactions between all electrons and ions are computed explicitly. We find that the non-Debye sheath can be extrapolated from the Debye sheath parameters with small corrections. We find that these parameters are roughly consistent with previous particle-in-cell code estimates, pointing to densities in the range 10 24 -10 25 m À3 . The high surface fields implied by these results could produce field emission that would short the sheath and cause an instability in the time evolution of the arc, and this mechanism could limit the maximum density and surface field in the arc. These results also provide a way of understanding how the properties of the arc depend on the properties (sublimation energy, for example) of the metal. Using these results, and equating surface tension and plasma pressure, it is possible to infer a range of plasma densities and sheath potentials from scanning electron microscope images of arc damage. We find that the high density plasma these results imply and the level of plasma pressure they would produce is consistent with arc damage on a scale 100 nm or less, in examples where the liquid metal would cool before this structure would be lost. We find that the submicron component of arc damage, the burn voltage, and fluctuations in the visible light production of arcs may be the most direct indicators of the parameters of the dense plasma arc, and the most useful diagnostics of the mechanisms limiting gradients in accelerators.

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Section: Simulation Techniquementioning

confidence: 99%

Sheath parameters for non-Debye plasmas: Simulations and arc damage

Морозов

Norman

Insepov

et al. 2012

Phys. Rev. ST Accel. Beams

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“…The numerical propagation is accomplished by a standard Velocity-Verlet algorithm [54,55] extended by a hierarchical treatment of close colliding particles which are propagated as subsystems (see [56] for details) and using an adaptive time step. Such MD simulations have already been extensively tested and successfully applied for investigations of the dynamic response of a TCP with regularized potentials, see [57,58]. By the MD simulations basically all correlations and many-body effects of classical many-body systems can be taken into account.…”

Section: A Numerical Treatmentsmentioning

confidence: 99%

Microfield distributions in strongly coupled two-component plasmas

2005

Self Cite

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The electric microfield distribution at charged particles is studied for two-component electron-ion plasmas using molecular dynamics simulation and theoretical models. The particles are treated within classical statistical mechanics using an electron-ion Coulomb potential regularized at distances less than the de Broglie length to take into account the quantum-diffraction effects. The potential-of-mean-force (PMF) approximation is deduced from a canonical ensemble formulation. The resulting probability density of the electric microfield satisfies exactly the second-moment sum rule without the use of adjustable parameters. The correlation functions between the charged radiator and the plasma ions and electrons are calculated using molecular dynamics simulations and the hypernetted-chain approximation for a two-component plasma. It is shown that the agreement between the theoretical models for the microfield distributions and the simulations is quite good in general.

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“…N i and N e are the numbers of ions and electrons (N = N i + N e ), R i and q i are the ion coordinates and charges, r k are the electron coordinates, σ ei = σ ee = 0.318 nm are the parameters responsible for the potential correction at short distances, U ext is an external field potential which may include wall boundaries as described below. This form of the interaction potential U has been used in MD studies of uniform nonideal plasmas [30] and simulations of the ionized sodium nanoclusters [22,31]. In our case it is important that this potential is close to the effective particle interaction in WPMD.…”

Section: Classical Molecular Dynamicsmentioning

confidence: 99%

Reflecting Boundary Conditions for Classical and Quantum Molecular Dynamics Simulations of Nonideal Plasmas

Lavrinenko

Морозов

Valuev

2016

Contrib. Plasma Phys.

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The influence of boundary conditions for the classical and wave packet molecular dynamics (MD) simulations of nonideal electron-ion plasma is studied. We start with the classical MD and perform a comprehensive study of convergence of the per-particle potential energy and pressure with the number of particles using both the nearest image method (periodic boundaries) and harmonic reflective boundaries. As a result an error caused by finiteness of the simulation box is estimated. Moreover electron oscillations given by the spectra of the current autocorrelation function are analyzed for both types of the boundary conditions. A special attention is paid to the reflecting boundaries since they prevent wave packet spreading in the Wave Packet MD. To speed up classical MD simulations we use the GPU-accelerated code.

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Dynamic response of two‐component model plasmas

Cited by 16 publications

References 13 publications

Sheath parameters for non-Debye plasmas: Simulations and arc damage

Sheath parameters for non-Debye plasmas: Simulations and arc damage

Microfield distributions in strongly coupled two-component plasmas

Reflecting Boundary Conditions for Classical and Quantum Molecular Dynamics Simulations of Nonideal Plasmas

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