Considerations of stimulated sideward scattering in NIF ignition-scale hohlraums

It's prudent to consider the possibility of stimulated Raman and Brillouin sideward scattering in NIF ignition-scale hohlraums. NIF beam spots are quite large (with diameter $>$1mm), and the gradient threshold intensities for these instabilities are rather low. Some simple calculations are given for the convective gain of sideward scattering assuming heavily-damped electrostatic waves. A possible enhancement of sideward scattering in the azimuthal direction is examined. Various ways to detect sideward scattering and its effects are discussed. For seeded angular scattering in the region where the laser beams overlap, see recent calculations by P. Michel \textit{et. al}.\footnote{P. Michel \textit{et. al}., 39$^{th}$ Anomalous Absorption Conference, Bodega Bay, CA (June 14-19, 2009)}