Vlasov models for kinetic Weibel-type instabilities. (5th January 2017)

• Record Type: Journal Article
• Authors: Ghizzo, A.; Sarrat, M.; Del Sarto, D.
• Is Part Of: Journal of plasma physics. Volume 83:Number 1(2017)
• Publication Date: 2017-01-05
• Subjects: plasma nonlinear phenomena, -- plasma simulation; Plasma (Ionized gases) -- Periodicals; 530.4405
• DOI: 10.1017/S0022377816001215
• Languages: English
• ISSNs: 0022-3778

Abstract

Abstract : The Weibel instability, driven by a temperature anisotropy, is investigated within different kinetic descriptions based on the semi-Lagrangian full kinetic and relativistic Vlasov–Maxwell model, on the multi-stream approach, which is based on a Hamiltonian reduction technique, and finally, with the full pressure tensor fluid-type description. Dispersion relations of the Weibel instability are derived using the three different models. A qualitatively different regime is observed in Vlasov numerical experiments depending on the excitation of a longitudinal plasma electric field driven initially by the combined action of the stream symmetry breaking and weak relativistic effects, in contrast with the existing theories of the Weibel instability based on their purely transverse characters. The multi-stream model offers an alternate way to simulate easily the coupling with the longitudinal electric field and particularly the nonlinear regime of saturation, making numerical experiments more tractable, when only a few moments of the distribution are considered. Thus a numerical comparison between the reduced Hamiltonian model (the multi-stream model) and full kinetic (relativistic) Vlasov simulations has been investigated in that regime. Although nonlinear simulations of the fluid model, including the dynamics of the pressure tensor, have not been carried out here, the model is strongly relevant even in the three-dimensional case.