Effects of axial magnetic fields on backward Raman scattering in inhomogeneous plasmas

The effects of an axial magnetic field on the convective amplification and the threshold intensity of Raman backscattering instability in an underdense, inhomogeneous plasma is investigated. Two cases of incident pump wave were considered. For the R-circularly polarization case it is shown that the amplification factor increases with the magnetic field, it also increases with the plasma density while the threshold intensity decreases. For the L-circularly polarization case, it is shown that the amplification factor decreases as the magnetic field and the plasma density increase, while the threshold intensity increases as the magnetic field increases but it decreases as the plasma density increases.