  Stimulated Raman scattering (SRS) in plasma in the degenerate regime is
studied theoretically and numerically. Different from normal SRS with the
non-degenerate eigen electrostatic mode excited, the degenerate SRS is
developed at plasma density $n_e>0.25n_c$ when the laser amplitude is larger
than a certain threshold. To satisfy the phase-matching conditions of frequency
and wavenumber, the excited electrostatic mode has a constant frequency around
half of the incident light frequency $\omega_0/2$, which is no longer the
non-degenerate eigenmode of electron plasma wave $\omega_{pe}$. Both the
scattered light and the electrostatic wave are trapped in plasma with their
group velocities being zero. Super hot electrons are produced by the degenerate
electrostatic wave. Our theoretical model is validated by particle-in-cell
simulations. The SRS driven in this degenerate regime is an important laser
energy loss mechanism in the laser plasma interactions as long as the laser
intensity is higher than $10^{15}$W/cm$^2$.
