An improved masking method for absorbing boundaries in electromagnetic particle simulations Original Research Article

We have developed a new scheme to mask electromagnetic fields for absorbing boundaries used in electromagnetic particle codes. The conventional masking method can suppress reflection of various plasma waves by assigning large damping regions for absorbing boundaries. It requires substantial computer memory and processing time. We introduce two new parameters to control absorption of outgoing electromagnetic waves. The first parameter is a damping parameter to change the effective length of damping regions. The second parameter is a retarding parameter to change phase velocities of electromagnetic waves in the damping regions. As a new masking method, we apply both damping and retarding factors. We also found that the best absorption of outgoing waves is realized with a combination of a smaller damping factor and a larger retarding factor. The new method allows us to reduce the size of damping regions substantially.