A Three-Axis Spherical Void Electrodynamic Levitator-Trap
S. Arnold
Rev.Sci.Inst. 62, 3025-3028(1991)

By adding two additional electrodes to the equator of a spherical void electrodynamic levitator trap (SVELT) one can balance static forces on a microparticle independently along three perpendicular axes. The balance equations are derived and a joy stick based controller is introduced for manipulating the electric field vector at the center of the SVELT. With this device, one can eliminate stray fields at the "null" point and center a particle to a limit set only by brownian forces in the electrodynamic pseudopotential. This limit is calculated and its importance for microphotography is discussed.