Turbulence in plasmas is a very challenging problem since it involves wave-particle interactions,which are responsible for phenomena such as plasma dissipation, acceleration mechanisms, heating,temperature anisotropy, and so on. In this work, a hybrid Vlasov-Maxwell numerical code isemployed to study local kinetic processes in a two-dimensional turbulent regime. In the presentmodel, ions are treated as a kinetic species, while electrons are considered as a fluid. As recentlyreported in [S. Servidio, Phys. Rev. Lett. 108, 045001 (2012)], nearby regions of strong magneticactivity, kinetic effects manifest through a deformation of the ion velocity distribution function thatconsequently departs from the equilibrium Maxwellian configuration. Here, the structure of turbulenceis investigated in detail in phase space, by evaluating the high-order moments of the particlevelocity distribution, i.e., temperature, skewness, and kurtosis. This analysis provides quantitativeinformation about the non-Maxwellian character of the system dynamics. This departure from localthermodynamic equilibrium triggers several processes commonly observed in many astrophysicaland laboratory plasmas

Hybrid Vlasov-Maxwell simulations of two-dimensional turbulence in plasmas

VALENTINI, Francesco;SERVIDIO, SERGIO;VELTRI, Pierluigi
2014

Abstract

Turbulence in plasmas is a very challenging problem since it involves wave-particle interactions,which are responsible for phenomena such as plasma dissipation, acceleration mechanisms, heating,temperature anisotropy, and so on. In this work, a hybrid Vlasov-Maxwell numerical code isemployed to study local kinetic processes in a two-dimensional turbulent regime. In the presentmodel, ions are treated as a kinetic species, while electrons are considered as a fluid. As recentlyreported in [S. Servidio, Phys. Rev. Lett. 108, 045001 (2012)], nearby regions of strong magneticactivity, kinetic effects manifest through a deformation of the ion velocity distribution function thatconsequently departs from the equilibrium Maxwellian configuration. Here, the structure of turbulenceis investigated in detail in phase space, by evaluating the high-order moments of the particlevelocity distribution, i.e., temperature, skewness, and kurtosis. This analysis provides quantitativeinformation about the non-Maxwellian character of the system dynamics. This departure from localthermodynamic equilibrium triggers several processes commonly observed in many astrophysicaland laboratory plasmas
SOLAR-WIND TURBULENCE; TEMPERATURE ANISOTROPY; MAGNETIC RECONNECTION
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/138161
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