Numerical investigation of a three-dimensional four field model for collisionless magnetic reconnection |
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Authors: | D Grasso D BorgognoE Tassi |
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Institution: | a CNR Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Dipartimento di Energetica, Politecnico di Torino Corso Duca degli Abruzzi 24, I-10129 Torino, Italy b Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy c Centre de Physique Théorique, CNRS - Aix-Marseille Universités, Campus de Luminy, Case 907, F-13288 Marseille Cedex 09, France |
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Abstract: | In this paper we present the numerical investigation of a three-dimensional four field model for magnetic reconnection in collisionless regimes. The model describes the evolution of the magnetic flux and vorticity together with the perturbations of the parallel magnetic and velocity fields. We explored the different behavior of vorticity and current density structures in low and high β regimes, β being the ratio between the plasma and magnetic pressure. A detailed analysis of the velocity field advecting the relevant physical quantities is presented. We show that, as the reconnection process evolves, velocity layers develop and become more and more localized. The shear of these layers increases with time ending up with the occurrence of secondary instabilities of the Kelvin-Helmholtz type. We also show how the β parameter influences the different evolution of the current density structures, that preserve for longer time a laminar behavior at smaller β values. A qualitative explanation of the structures formation on the different z-sections is also presented. |
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Keywords: | Nonlinear dynamics Plasma instabilities Fluid instabilities Numerical simulations |
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