OSCILLATING CHARACTERISTICS OF CHARGED LEVITATED PARTICLES UNDER EXTERNAL ELECTRIC-FIELD IN A QUADRUPOLE LEVITATION TRAP

The oscillation and deformation of a free levitated charge particle under an externa time-varying electric field in a quadrupole levitation device with a pair of auxiliary electrodes ('boxer electrodes') is analysed. Particles under the superimposed external ac field can be manipulated into oscillating and orbiting movement by changing frequency and phase difference. The trajectories of the oscillating particle have been captured using a real-time image grabber with a high speed shutter facility. The finite element analysis is employed to assist in the complete specification of the electrodes. The prediction of the particle's oscillation is also determined through the location of the saddle point of the potential contours. The interpretation of this oscillating effect with regard to liquid spray drying together with other applications of particle processing is discussed.