Coupled models in low-frequency electromagnetic simulation LDRD Final Report 94-ERI-004

Responding to a need to include realistic chemistry and ionization in the driven plasmas in plasma-aided manufacture, we became convinced that existing computational tools were not able to fulfill our requirements. In response to this, we invented an entirely new approach to such problems. Our approach is to generalize the capabilities of existing methods: Particle-In-Cell (PIC) contains the required details of the distributions but becomes overwhelming expensive when applied to realistic, multidimensional problems. The common alternative, the hydrodynamic model, has simply lost the ability to model this science because of the simple fluid assumption. Our solution, GAPH (for Grid and Particle Hydrodynamics), retains the kinetic capabilities of PIC while using fluid concepts within each particle to control the incredible expense. The coupling of these two methods has resulted in a very powerful new algorithm that is now being applied to a range of programmatic problems throughout LLNL that now far outstrips the initial applications area.