Abstract

The development of high intensity lasers has led to the possibility of observing relativistic effects when a laser pulse interacts with a fully ionized plasma. The propagation of high intensity laser pulses through a fully ionized plasma has practical applications for compact x-ray lasers [1,2], laser-plasma-based particle accelerators [3], and advanced inertial confinement fusion schemes [4], The relativistic filamentation instability [5] can lead to modifications of the propagating pulse by spatially modulating the laser intensity transverse to the direction of propagation; growth of the instability can lead to spreading of the beam as the result of the density modulation set up by the filamented ponderomotive force. The beam propagation needs to be understood before further nonlinear effects are investigated [6,7]. Previous experimental studies of high-intensity laser pulses have employed neutral gases which are ionized by the propagating pulse [8]. That technique is limited by technical constraints to relatively low electron densities (≤ 10¹⁹ cm^-3) and introduces the possibility of the modification of the propagation behavior by the formation of an ionization front at the leading edge of the pulse [8].

© 1997 Optical Society of America