  Raman amplification of a short laser pulse off a long laser beam has been
demonstrated successfully for moderate probe intensities ($\sim 10^{16}$
W/cm$^2$) and widths ($\sim 50$ micron). However, truly competitive intensities
can only be reached if the amplification process is carried out at much higher
probe intensities ($10^{17}-10^{18}$ W/cm$^2$ after amplification) and widths
(1-10 mm). In this paper we examine the opportunities and challenges provided
by this regime through the first 2-dimensional particle-in-cell simulations
using wide pulses. A parameter window is identified in which a 10 TW, 600
$\mu$m wide, 25 ps long laser pulse can be efficiently amplified to 2 PW peak
intensity.
