Transient Self-Focusing of an Intense Short Pulse Laser in Magnetized Plasma

Transient self focusing of an intense short pulse laser in a plasma is strongly modified by a transverse magnetic field. The laser with Gaussian radial distribution of intensity exerts a ponderomotive force on electrons and sets in ambipolar diffusion of the plasma. The ambient magnetic field, however, strongly inhibits the process, when the electron Larmor radius is comparable to or shorter than the laser spot size r0. As the plasma density is depleted, the laser beam becomes more and more self-focused