Direct observation of microparticle gyromotion in a magnetized direct current glow discharge dusty plasma

Laboratory observations of oscillatory motion of charged microparticles have been made in an argon dc glow discharge plasma created within a strong dc magnetic field. Measurements of the oscillation frequency and amplitude are consistent with the gyromotion of magnetized dust grains under the ambient plasma conditions. The measurements provide an effective method for the noninvasive determination of the charge on the observed microparticles. The observations also seem to indicate that the neutral drag force on the dust grains may be smaller than anticipated from the classical estimation. (C) 2004 American Institute of Physics.