Covariant Self-force Regularization of a Particle Orbiting a Schwarzschild Black Hole - Mode Decomposition Regularization -

Covariant structure of the self-force of a particle in a general curved background has been made clear in the cases of scalar [Quinn], electromagnetic [DeWittBrehme], and gravitational charges [QuinnWald]. Namely, what we need is the part of the self-field that is non-vanishing off and within the past light-cone of particle's location, the so-called tail. The radiation reaction force in the absence of external fields is entirely contained in the tail. In this paper, we develop mathematical tools for the regularization and propose a practical method to calculate the self-force of a particle orbiting a Schwarzschild black hole.