Virtual Prototyping of RF Weapons Robert E. Peterkin, Jr., Phillips Laboratory, Kirtland AFB, NM Description: High power radio frequency (RF) is generated by the interaction of charged matter with appropriately constructed conductors and dielectrics. High power RF weapons have three essential elements: a radiating structure, a cavity that couples RF energy to a relativistic electron beam, and a source of pulsed power to drive the beam and cavity. The high energy densities in such systems cause some portions of the normally solid materials to enter the ionized gas, or plasma, state. The Directed Energy Directorate of the Air Force Research Laboratory, Phillips Lab, has the Air Force responsibility for development of RF weapons, including both narrowband and ultrawideband RF weapons. Ambitious experimental efforts are in progress to support RF weapon development. The relevant experiments are complex and expensive. Experimental efforts, and consequently weapon development, are more timely and cost-effective if guided by scientific modeling and simulation, i.e., virtual prototyping. RF weapon systems can be modeled using Maxwell's equations and either the Lorentz Force law (for the kinetics of individual charged particles)or the Navier-Stokes compressible fluid equations (for the dynamics of a conducting gas). The resulting nonlinear system of partial differential equations is analytically intractable, and their numerical solution requires fine-grained resolution. Thus, computational modeling and simulation of RF devices, which is critical to their timely development, is computationally intensive. In this project, we will use three first-principle physics codes that have been developed over the past four years to run on scalable computing platforms with continuing funding from the Air Force Office of Scientific Research and the DoD HPCMP Common HPC Software Support Initiative to design novel RF systems. Assigned Site/System: NAVO T90, CEWES SP, ASC SP CTA: Computational Electromagnetics and Acoustics