Phase conjugation of microsecond laser pulses by forward Brillouin sca
ttering in the field of two intersecting pump beams with a near-single
-mode transverse structure is studied experimentally. The possibility
of performing this interaction with relatively low pump power densitie
s is demonstrated. This possibility allows one to realize phase conjug
ation of long pulses in the absence of the competitive effect of therm
al self-action.