Simulating NIF laser-plasma interaction with multiple SRS frequencies

Understanding the energetics of a NIF ignition hohlraum is important to achieving ignition. Laser-plasma interactions (LPI) can reduce the radiation drive if backscatter occurs, and can also affect the hohlraum energetics by modifying the laser beam energy deposition which in turn can alter the implosion symmetry. The addition of a second SRS frequency to the modeling code pF3d can capture physics which would otherwise have been omitted. In the case of a wide or bi-modal SRS spectrum, this physics can be important. We discuss the modifications to the pF3d computational model, and exhibit its effect in a NIF ignition-relevant LPI simulation.