Multiple-GPU-Based Simulation of Ka-Band Helix Traveling Wave Tube

The finite-difference time-domain (FDTD) algorithm and the particle-in-cell (PIC) method-based simulation are classic approaches to design and optimize the helix traveling wave tubes (TWTs). In this article, a multiple-graphics processing unit (GPU)-based 3-D-FDTD-PIC parallel program is developed to complete the full-wave simulation of a Ka-band helix TWT in the time domain. The specific parallel simulation scheme is given. The code based on compute unified device architecture (CUDA) and message passing interface (MPI) can run on a scalable heterogeneous cluster consisting of multiple CPUs and GPUs, substantially improving the simulation speed and shortening the development period of TWTs. In this article, the specific parameters of the experimental TWT are given. The simulation results are found basically consistent with the measured values and theoretical analysis, verifying the correctness of this code. Moreover, this program can realistically restore the physical processes occurring in the tube in a short period of time, which means it can be applied as an efficient simulation tool for further research of TWTs or even other microwave power devices based on beam-wave interaction.