Title: Plasmon excitation in metal slab by fast point charge: The role of additional boundary conditions in quantum hydrodynamic model

We study the wake effect in the induced potential and the stopping power due to plasmon excitation in a metal slab by a point charge moving inside the slab. Nonlocal effects in the response of the electron gas in the metal are described by a quantum hydrodynamic model, where the equation of electronic motion contains both a quantum pressure term and a gradient correction from the Bohm quantum potential, resulting in a fourth-order differential equation for the perturbed electron density. Thus, besides using the condition that the normal component of the electron velocity should vanish at the impenetrable boundary of the metal, a consistent inclusion of the gradient correction is shown to introduce two possibilities for an additional boundary condition for the perturbed electron density. We show that using two different sets of boundary conditions only gives rise to differences in the wake potential at large distances behind the charged particle. On the other hand, the gradient correction in the quantum hydrodynamic model is seen to cause a reduction in the depth of the potential well closest to the particle, and a reduction of its stopping power. Even for a particle moving in the center of the slab, we observemore » nonlocal effects in the induced potential and the stopping power due to reduction of the slab thickness, which arise from the gradient correction in the quantum hydrodynamic model.« less

School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

(Canada)

Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

Publication Date:

OSTI Identifier:

22299657

Resource Type:

Journal Article

Resource Relation:

Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BOUNDARY CONDITIONS; CHARGED PARTICLES; CORRECTIONS; DIFFERENTIAL EQUATIONS; ELECTRON DENSITY; ELECTRON GAS; EXCITATION; HYDRODYNAMIC MODEL; METALS; POINT CHARGE; REDUCTION; STOPPING POWER