<scp>UNIPIC</scp> code for simulations of high power microwave devices

TLDR

The paper introduces UNIPIC, a new fully electromagnetic particle‑in‑cell code for simulating high‑power microwave generation. UNIPIC implements a 2.5‑dimensional, object‑oriented C++ framework that updates electromagnetic fields with second‑order FDTD, applies the relativistic Newton–Lorentz force to particles, uses convolutional perfectly matched layers for open boundaries, and incorporates a weakly conditional‑stable FDTD/CP‑FDTD hybrid to model curved surfaces, all accessible via a graphical interface and runnable on Windows, Linux, and Unix. Numerical tests on representative high‑power microwave devices show that UNIPIC’s results agree well with those from established PIC codes.

Abstract

In this paper, UNIPIC code, a new member in the family of fully electromagnetic particle-in-cell (PIC) codes for simulations of high power microwave (HPM) generation, is introduced. In the UNIPIC code, the electromagnetic fields are updated using the second-order, finite-difference time-domain (FDTD) method, and the particles are moved using the relativistic Newton–Lorentz force equation. The convolutional perfectly matched layer method is used to truncate the open boundaries of HPM devices. To model curved surfaces and avoid the time step reduction in the conformal-path FDTD method, CP weakly conditional-stable FDTD (WCS FDTD) method which combines the WCS FDTD and CP-FDTD methods, is implemented. UNIPIC is two-and-a-half dimensional, is written in the object-oriented C++ language, and can be run on a variety of platforms including WINDOWS, LINUX, and UNIX. Users can use the graphical user’s interface to create the geometric structures of the simulated HPM devices, or input the old structures created before. Numerical experiments on some typical HPM devices by using the UNIPIC code are given. The results are compared to those obtained from some well-known PIC codes, which agree well with each other.