Gyrofluid simulations of turbulence and reconnection in space plasmas

Abstract

A Hamiltonian two-field gyrofluid model is used to investigate the dynamics of an electron-ion collisionless plasma subject to a strong ambient magnetic field, within a spectral range extending from the magnetohydrodynamic (MHD) scales to the electron skin depth. This model isolates Alfvén, Kinetic Alfvén and Inertial Kinetic Alfvén waves that play a central role in space plasmas, and extends standard reduced fluid models to broader ranges of the plasma parameters. Recent numerical results are reviewed, including (i) the reconnection-mediated MHD turbulence developing from the collision of counter-propagating Alfvén wave packets, (ii) the specific features of the cascade dynamics in strongly imbalanced turbulence, including a possible link between the existence of a spectral transition range and the presence of co-propagating wave interactions at sub-ion scales, for which new simulations are reported, (iii) the influence of the ion-to-electron temperature ratio in two-dimensional collisionless magnetic reconnection. The role of electron finite Larmor radius corrections is pointed out and the extension of the present model to a four-field gyrofluid model is discussed. Such an extended model accurately describes electron finite Larmor radius effects at small or moderate values of the electron beta parameter, and also retains the coupling to slow magnetosonic waves.

11 figures, 52 pages

References in corpus (20)

• The Evolution and Role of Solar Wind Turbulence in the Inner Heliosphere
• Nature of Kinetic Scale Turbulence in the Earth's Magnetosheath
• Magnetic reconnection as a driver for a sub-ion scale cascade in plasma turbulence
• Spectral Slope Variation at Proton Scales from Fast to Slow Solar Wind
• Collisionless Reconnection in Magnetohydrodynamic and Kinetic Turbulence
• Magnetohydrodynamic turbulence mediated by reconnection
• Reconnection-Driven Energy Cascade in Magnetohydrodynamic Turbulence
• Violation of the zeroth law of turbulence in space plasmas
• The In Situ Signature of Cyclotron Resonant Heating
• Energy dynamics and current sheet structure in fluid and kinetic simulations of decaying magnetohydrodynamic turbulence
• The Ion Transition Range of Solar Wind Turbulence in the Inner Heliosphere: Parker Solar Probe Observations
• Three-dimensional magnetic reconnection in particle-in-cell simulations of anisotropic plasma turbulence
• Imbalanced kinetic Alfvén wave turbulence: from weak turbulence theory to nonlinear diffusion models for the strong regime
• MHD-kinetic transition in imbalanced Alfvénic turbulence
• Dynamic Phase Alignment in Inertial Alfven Turbulence
• Turbulent regimes in collisions of 3D Alfvén-wave packets
• Modeling imbalanced collisionless Alfvén wave turbulence with nonlinear diffusion equations
• Influence of ion-to-electron temperature ratio on tearing instability and resulting subion-scale turbulence in a low-${\beta }_e$ collisionless plasma
• A Hamiltonian gyrofluid model based on a quasi-static closure
• Direct kinetic Alfvén wave energy cascade in the presence of imbalance