July 25, 2023
Numerical study of field reversed configuration (FRC) acceleration, merging and non-equilibrium stability will be performed using the 3D nonlinear hybrid code (HYM), developed at PPPL. Helion Energy Inc. fusion concept is based on FRC acceleration, merging and compression to achieve a high temperature plasma. Helion’s 6th Prototype, Trenta, was comprised of two magnetically driven accelerators, each of which produced and accelerated an FRC to high velocity while simultaneously compressing it. During the FRCs merging, the kinetic energy is converted to ion thermal energy, while the magnetic compression further increases the plasma temperature. Hybrid version of the HYM code includes the fluid electrons and full-orbit kinetic (Particle-In-Cell) description of the thermal ions. In the simulations, the FRC parameters and profiles will be varied to understand their effects on FRC stability during the acceleration phase and the merging process and estimate the possible stability limits. Three-dimensional and 2D kinetic simulations of FRC merging will be compared with the corresponding MHD results to understand the effects of kinetic ions on FRC merging and investigate stability properties of FRCs with fast changing plasma parameters. 3D hybrid simulations of FRC acceleration will also be performed to study the FRC stability properties during the acceleration/translation phase and investigate how the stability time scales depend on the plasma parameters within and outside the experimental range. The simulation results will be used to identify the corresponding signatures in the experimental diagnostics and compared against the actual experimental measurements. Improved understanding the physics of the FRC merging, its dependence on the plasma parameters, and scaling with the device size is important for achieving the goals of the Helion experimental program and planning of the next-step fusion prototype. The scientific contributions from the Department of Energy funded