Simulation of fast ignitor physics using GaPH (a fluid element particle in cell) method

Summary form only given, as follows. A new plasma/fluid transport algorithm, called GaPH, is developed, which retains the strengths of the particle and hydrodynamic methods. By including internal velocity characteristics of real particles within each finite size macroparticle, a redundancy is introduced in the representation of the real particle distribution. The internal velocity distribution within each particles evolves hydrodynamically. The result of this evolution is then fit to three new particles. The hydrodynamic evolution establishes the partitioning of moments into central and expansion particles. Such aggressive increases in the number of individual particles probe for emerging features in the distribution. If features fail to materialize, the redundancy that results from the internal velocity distribution is exploited to allow aggressive merging to reduce the number of particles needed to represent the distribution. Therefore, GaPH gives particle simulation results without the computational expense. Using GaPH, we are planning to simulate the propagation of suprathermal electrons from critical density to the high density core and their interactions with background plasma in order to provide a basis for theoretical description of fast ignitor physics. In order to model this process with GaPH, work is now underway to add essential new capabilities, including a radiation model, equation of state, and atomic collisions.