Extension of the Modeling of Collisional Blooming and Straggling of the Electron Beam in the Fast Ignition Scenario

When an electron beam is fired into an imploding target in order to initiate a fastignition-type propagating burn, spreading of the electrons occurs within the beam. The spread in the direction of motion (straggling) and the spread perpendicular to the direction of motion (blooming), as well as the energy lost as a result of these phenomena, can be defined by three equations. Previously, a program was written that added the effects of blooming, straggling, and energy deposition to an existing straight-line model. This model functioned by initially creating a single electron which was then split into several simulated electrons of different directions and energies as the probability of spreading increased. However, this method resulted in a too-large number of simulated electrons, consuming large amounts of computer memory. The program was amended by the addition of a protocol to combine simulated electrons that are in close proximity, effectively treating them as one entity and allowing for greater efficiency. This algorithm has been successful in shortening runtime and decreasing memory requirements and was tested for realistic implosion conditions in which the plasma density is nonuniform.