Electron viscosity in strong laser field

The research in collisional dissipation processes play an important part in the problem of laser-plasma interaction. The collisional model of the absorption of laser radiation can work for ultrashort laser pulses only, when the duration of a pulse is shorter than the characteris-tic time of instabilities. These ultrashort pulses are of great importance in various practical problems (for example, recombination lasers [1]). Originally the kinetic theory of transport phenomena was advanced for weak fields [2], when the electron velocity in electromagnetic wave V = eE/mω cannot exceed the thermal velocity u = Te/m. The analytical treatment of the problem is available for almost equilib-rium systems, in which the distribution function is represented as a local equilibrium part and small corrections caused by the factors, which disturb the equilibrium. It is also suggested that the action of these factors results in slow changing of the distribution function in comparison with the time between particle collisions. In the problem of laser-plasma interaction it means that laser frequency ω is less than collision frequency νei. With the advent of high-power lasers the studies of transport phenomena in strong high-frequency fields have become urgent. In this regime electron-ion (e-i) collisions are shown to be suppressed by the factor (V/u)3 [3] νei