Brillouin backscattering instability is investigated in
inhomogeneous collisional plasma. The slow-coupling equations
for the instability in a medium with linear density ramp are
obtained. For large inhomogeneity scale length, the homogeneous
growth rate is found to be modified by a factor of
[1/square root(2) times square root(ω02/
(ω02 + νe2) +
ω0/square root(ω02 +
νe2))]
For the convective instability, the amplification factor is found to
be
[Λ = (|γB0|2/2β)(ω02/ω02 + νe2)]
The presence of collisions leads to a reduction in both the growth
rate and the amplification factor, where the threshold intensity for the
instability to occur increases.