Strong self‐focusing due to the ponderomotive force in plasmas

Self‐focusing of cylindrical beams due to the ponderomotive force behaves quite differently for the full exponential nonlinearity than for the weak, cubic‐nonlinearity limit. Steady self‐trapped propagation becomes possible for arbitrary incident powers. Self‐focusing becomes a periodic oscillatory phenomenon, rather than a catastrophic process in which the light intensity increases without limit.