Brief Introduction and Recent Applications of a Large-Scale Parallel Three-Dimensional PIC Code Named NEPTUNE3D

This paper introduces a large-scale parallel 3-D fully electromagnetic particle-in-cell code named Nonlinear Evolution of Plasma-interaction Technology Under Nonneutral Environment-Three Dimensional (NEPTUNE3D) developed with the support of a parallel adaptive structured mesh application infrastructure JASMIN. NEPTUNE3D can be used to simulate beam-wave interactions in high-power microwave (HPM) generators. Some novel parallelization techniques are adopted in the NEPTUNE3D code for high parallel efficiency and good scalability. Some real-world HPM devices have been successfully simulated by NEPTUNE3D, such as the relativistic backward wave oscillator (RBWO), the magnetically insulated line oscillator (MILO), the virtual cathode oscillator, and the relativistic klystron amplifier. In this paper, two recent simulation examples are presented. The first is simulations of a knife-edge cathode RBWO, using 128 processors very efficiently. The second example is simulations of a MILO with a plate-inserted mode-transducing antenna, modeled using 27 million cells, 3 million particles, and 1024 processors with relatively high parallel efficiency.