Nonlinear gyrofluid simulations of collisionless reconnection
- Istituto Sistemi Complessi, CNR, Via dei Taurini 19, 00185 Rome (Italy) and Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)
- Centre de Physique Theorique, CNRS-Aix-Marseille Universites, Campus de Luminy, case 907, F-13288 Marseille Cedex 09 (France)
- Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712-1060 (United States)
The Hamiltonian gyrofluid model recently derived by Waelbroeck et al. [Phys. Plasmas 16, 032109 (2009)] is used to investigate nonlinear collisionless reconnection with a strong guide field by means of numerical simulations. Finite ion Larmor radius gives rise to a cascade of the electrostatic potential to scales below both the ion gyroradius and the electron skin depth. This cascade is similar to that observed previously for the density and current in models with cold ions. In addition to density cavities, the cascades create electron beams at scales below the ion gyroradius. The presence of finite ion temperature is seen to modify, inside the magnetic island, the distribution of the velocity fields that advect two Lagrangian invariants of the system. As a consequence, the fine structure in the electron density is confined to a layer surrounding the separatrix. Finite ion Larmor radius effects produce also a different partition between the electron thermal, potential, and kinetic energy, with respect to the cold-ion case. Other aspects of the dynamics such as the reconnection rate and the stability against Kelvin-Helmholtz modes are similar to simulations with finite electron compressibility but cold ions.
- OSTI ID:
- 21432215
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 8; Other Information: DOI: 10.1063/1.3475440; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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