Self-sustained plasma turbulence due to current diffusion

Plasma turbulence and anomalous transport due to the electrostatic and electromagnetic current diffusive interchange modes are studied analytically and numerically, based on the magnetohydrodynamic model. Analytically, the ion and electron thermal conductivities which are valid in the electromagnetic regime are evaluated by use of the one-point renormalization method and compared with those in the electrostatic regime. It is found that the electromagnetic electron nonlinearity in Ohm's law further drives a new instability, which is stronger than that in the electrostatic case. Numerically, two dimensional nonlinear simulations are performed to investigate the nonlinear destabilization mechanisms and the characteristics of the self-sustained turbulence. The validity of the self-sustained turbulence theory based on the one-point renormalization method is also confirmed by numerical results.