Theoretical derivation of laser induced plasma profiles

The hydrodynamic modification of an expanding plasma by coherent radiation for polarization out of the plane of incidence is investigated theoretically in the absence of parametric and modulational instabilities. The pondermotive force of the incident wave modifies the plasma flow from that of a rarefaction wave into a subsonic flow in the overdense region with a transition to supersonic flow at less than critical density. A constraint imposed at the sonic transition point allows a complete determination of the equilibrium as observed in simulations. The theory predicts that the average flow in the subcritical density region scales as the square root of the incident power.