Generalized Harmonic Gauge Drivers

Recent work on the development of gauge drivers for the generalized harmonic Einstein system will be presented. These new gauge drivers allow a large class of gauge (i.e. coordinate) conditions to be imposed while keeping the generalized harmonic representation of the Einstein system hyperbolic. This class of gauge conditions includes as special cases many of the standard conditions used in numerical relativity: e.g. Bona-Masso slicing, Gamma-drivers, etc. New gauge-controlling boundary conditions will be discussed, along with numerical results that illustrate the effectiveness of this new gauge driver system.