Theory of nonlocal transport in laser produced plasmas

Abstract

More than twenty years ago the experimental laser plasma researcher found the phenomena of the electron heat flux inhibition. It was found that the electron heat flux of a collisionless plasma is much smaller than the usual Knudsen heat flux which is estimated in the frame of the ideas of the theory of rarefied gases. Previously the inhibition phenomenon was connected with the ion-acoustic plasma turbulence, but a lot of numerical simulations of the collisional plasma gave indications onto the collisional nature of the inhibition phenomena. It was no real understanding of the physical role of collisions because of the difficulties to understand the numerical calculations. Now we have elaborated the analytic kinetic theory that describes the role of the collisional low velocity electrons in conditions when the thermal electrons are collisionless. Instead of the usually discussed role of the hot electrons we have discovered the important properties of the cold subthermal electrons. It permits us to formulate new analytic laws for the nonlocal transport and to understand the new reason of the old electron heat flux inhibition phenomena that can be connected with the long range Coulomb field of the charged particles.