Self-consistent PIC Simulations of Neutron Generation from Intense Laser-plasma Interactions*

High intensity laser-plasma interactions have the potential to produce bright, compact neutron sources. Recent experiments using a deuterium jet have demonstrated the generation of up to $10^{10}$ neutrons per shot, but the details of the laser-plasma interactions and deuteron heating are not yet understood. We have followed a Direct Simulation Monte Carlo (DSMC) approach to model fusion reactions self-constentily in PIC codes, inspired by the methods used for Coulomb collisions. This module has been implemented and tested in the OSIRIS PIC code. We will discuss the implementation options and validity tests and will present results from novel simulations of neutron generation in the interaction of intense lasers with deuterium jets.