  We describe a new geometry for electrostatic actuators to be used in
sensitive laser interferometers. The arrangement consists of two plates at the
sides of the mirror (test mass), and therefore does not reduce its clear
aperture as a conventional electrostatic drive (ESD) would do. Using the sample
case of the AEI-10m prototype interferometer, we investigate the actuation
range and influences of relative misalignment of the ESD plates in respect to
the test mass. We find that in the case of the AEI-10 m prototype
interferometer, this new kind of ESD could provide a range of 0.28 micrometer
when operated at a voltage of 1 kV. In addition, the geometry presented is
shown to provide a reduction factor of about 100 in the magnitude of actuator
motion coupling to test mass displacement. We show that therefore in the
specific case of the AEI-10m interferometer it is possible to mount the ESD
actuators directly on the optical table, without spoiling the seismic isolation
performance of the triple stage suspension of the main test masses.
