LASER WAKE-FIELD ACCELERATION AND OPTICAL GUIDING IN A HOLLOW PLASMA CHANNEL

The accelerating and focusing wake fields that can be excited by a short laser pulse in a hollow underdense plasma are examined. The evacuated channel in the plasma serves as an optical fiber to guide the laser pulse over many Rayleigh lengths. Wake fields excited by plasma current at the edge of the channel extend to the center where they may be used for ultrahigh gradient acceleration of particles over long distances. The wake field and equilibrium laser profiles are found analytically and compared to two-dimensional (2-D) particle-in-cell (PIC) simulations. Laser propagation is simulated over more than ten Rayleigh lengths. The accelerating gradients on the axis of a channel of radius c/ωp are of order of one-half of the gradients in a uniform plasma. For present high-power lasers, multi-GeV/m gradients are predicted. © 1995 American Institute of Physics.