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 un der an externa time-varying electric field in a quadrupole levitation device with a pair of auxiliary electrodes ('boxer electrodes') is ana lysed. Particles under the superimposed external ac field can be manip ulated into oscillating and orbiting movement by changing frequency an d phase difference. The trajectories of the oscillating particle have been captured using a real-time image grabber with a high speed shutte r facility. The finite element analysis is employed to assist in the c omplete specification of the electrodes. The prediction of the particl e's oscillation is also determined through the location of the saddle point of the potential contours. The interpretation of this oscillatin g effect with regard to liquid spray drying together with other applic ations of particle processing is discussed.