Benfenati Benfenati | University of Brescia (original) (raw)
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Istituto Nazionale di Astrofisica, FIRENZE, ITALY
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Papers by Benfenati Benfenati
Chaos: An Interdisciplinary Journal of Nonlinear Science, 2014
We report the results of numerical simulations for a model of a one component plasma (a system of... more We report the results of numerical simulations for a model of a one component plasma (a system of N point electrons with mutual Coulomb interactions) in a uniform stationary magnetic field. We take N up to 512, with periodic boundary conditions, and macroscopic parameters corresponding to the weak coupling regime, with a coupling parameter Γ = 1/64. We find that a transition from order to chaos takes place when the density is increased or the field decreased so that the ratio ωp/ωc between plasma and cyclotron frequencies becomes of order 1 (or equivalently the ratio rL/λD between Larmor radius and Debye length becomes of order 1). The result is in agreement with the theoretical prediction obtained in [1], on the basis of an old estimate of Iglesias, Lebowitz and MacGowan[2] for the intensity of the electric field acting on one electron and due to all the other ones. A comparison can be made with the threshold obtained from kinetic theory arguments, which corresponds to the condition νee/ωc = 1, where νee is the electron collision frequency. The latter threshold has a completely different dependence on the physical parameters and, for Γ = 1/64, gives a critical value of ωp about 80 times larger.
Chaos: An Interdisciplinary Journal of Nonlinear Science, 2014
We report the results of numerical simulations for a model of a one component plasma (a system of... more We report the results of numerical simulations for a model of a one component plasma (a system of N point electrons with mutual Coulomb interactions) in a uniform stationary magnetic field. We take N up to 512, with periodic boundary conditions, and macroscopic parameters corresponding to the weak coupling regime, with a coupling parameter Γ = 1/64. We find that a transition from order to chaos takes place when the density is increased or the field decreased so that the ratio ωp/ωc between plasma and cyclotron frequencies becomes of order 1 (or equivalently the ratio rL/λD between Larmor radius and Debye length becomes of order 1). The result is in agreement with the theoretical prediction obtained in [1], on the basis of an old estimate of Iglesias, Lebowitz and MacGowan[2] for the intensity of the electric field acting on one electron and due to all the other ones. A comparison can be made with the threshold obtained from kinetic theory arguments, which corresponds to the condition νee/ωc = 1, where νee is the electron collision frequency. The latter threshold has a completely different dependence on the physical parameters and, for Γ = 1/64, gives a critical value of ωp about 80 times larger.