Return current instability in laser heated plasmas

The localized heating of an underdense plasma by a focused laser beam has been studied with a kinetic Fokker–Planck code. Simulations show an inhibition of the electron heat flux in the region where temperature gradients are maximized. A time analysis of electron distribution function demonstrates that the heat flux inhibition does not interfere with the excitation of the return current ion acoustic instability. The conditions for onset of the instability and its possible effect on plasma transport are also discussed.