Rotation of dust particles in an inhomogeneous weak magnetic field in a DC glow discharge

We report an explanation for the opposite direction of the rotation of the charged dust particles above and below the Helmholtz coil in an inhomogeneous weak magnetic field in the direct current glow discharge. Experiments with monodispersed melamine-formaldehyde particles were performed in an argon plasma in an inhomogeneous weak magnetic field (with the induction values 4, 12, and 18 mT). The linear and angular velocities of rotational motion of the clusters of dust particles formed in regions with an inhomogeneous weak magnetic field above and below the Helmholtz coil were analyzed. The peculiarity is that the directions of rotation in these areas are opposite, whereas there is no rotational motion in the region of a uniform magnetic field. To explain these observations, the theoretical model that takes into account the magnetic field inhomogeneity and provides good agreement with experimental data is presented. Published under an exclusive license by AIP Publishing.