Preserving Gauss´s law during particle emission from general boundaries in electromagnetic particle codes

Preserving Gauss´s law during particle emission in electromagnetic codes is key for obtaining proper solutions in high emission current electromagnetic simulations. Tech-X´s electromagnetic PIC code VORPAL has recently been extended to cut cell geometries with arbitrary emission regions defined for a variety of emitters including (among others) thermal-field emitters and secondary emission. In this paper we present the general algorithms used for Gauss preserving particle emission (which can be applied to all sorts of EM particle simulation schemes) along with recent results.