Search

We found that steady-state paired-particle motion was often observed in a fine-particle cloud in the argon plasma produced by a 100-kHz high-frequency discharge. Monodispersed spherical silica particles with a diameter of $5.0~\mu \text{m}$ were trapped in the plasma. The 2-D motion of these charged particles was carefully recorded using a microscope camera, and their orbits and perturbation frequencies were analyzed. The loci and fast Fourier transform spectra of many paired particles were obtained. By moving the camera horizontally, 3-D images of the particles were recorded, and a 3-D map of the positions of charged particles was obtained. It is considered that the forces inducing the paired-particle motion were generated by the Debye shielding and the electric field surrounding the paired particles. [ABSTRACT FROM AUTHOR]

This paper reports the levitation of micro-organisms in the sheath of radio-frequency (RF) plasma. Based on simple force-balance calculations, the required electric field for the levitation of micro-organisms has been estimated. It is predicted that micro-organisms could levitate at the periphery of the sheath. Experimental results demonstrate the levitation of two species of bacillus micro-organisms Escherichia coli (E. coli) and Klebsiella pneumoniae in an RF plasma. The almost monodiverse Klebsiella pneumoniae levitating in the RF plasma formed an ordered state similar to a 2-D Coulomb crystal. Diverse E. coli particles demonstrate the tendency that the levitating height of micro-organisms decreases as the radius of particles increases. Levitating micro-organisms in plasmas can be referred as dusty plasmas. [ABSTRACT FROM AUTHOR]