  An initial-boundary value problem for a model of stimulated Raman scattering
was considered in [Moskovchenko E.A., Kotlyarov V.P., J. Phys. A: Math. Theor.
43 (2010), 055205, 31 pages]. The authors showed that in the long-time range
$t\to+\infty$ the $x>0$, $t>0$ quarter plane is divided into 3 regions with
qualitatively different asymptotic behavior of the solution: a region of a
finite amplitude plane wave, a modulated elliptic wave region and a vanishing
dispersive wave region. The asymptotics in the modulated elliptic region was
studied under an implicit assumption of the solvability of the corresponding
Whitham type equations. Here we establish the existence of these parameters,
and thus justify the results by Moskovchenko and Kotlyarov.
