Study of stimulated Raman scattering of laser speckles in the inertial confinement fusion regime using 2D2V Vlasov simulations*

We present simulations of stimulated Raman scattering occurring in laser speckles with laser parameters and plasma conditions typical of inertial confinement fusion experiments. Our simulations leverage recent advances in numerical methods for solving the Vlasov equation using high-order-accurate numerical schemes, permitting previously unreachable scales to be simulated in a 2D2V phase space. Our simulations include relativistic and collisional effects. The employed continuum representation of the particle distribution functions can be noiseless to machine precision. Such a property is useful for the precise study of instabilities, particularly those that are resonant in the far tail of the distribution. However, many applications benefit from the presence of noise that approximates physical thermal fluctuations, such as the study of simultaneous and competing instabilities (as is the case here). We describe a particle-based method to model fluctuations within continuum codes from which instabilities may subsequently grow.

 

*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344