Rotation of Dust Structures in a Magnetic Field in a DC Glow Discharge

We present the experimental results on influence of an external magnetic field on the dust particles which were suspended in the strata of a glow discharge, where the magnetic field was created using a Helmholtz coil. Observations were made in the strata that located between the coils, under the coil, and above the coil. We observed an interesting behavior of dust particles, which was not previously reported. It was revealed that the dust structure rotates clockwise above the coil and counterclockwise under the coil, while the dust structure located between the coils does not rotate. Experiments were performed with both mono-and poly-disperse dust particles at B <= 28 mT. The radial distribution of the angular velocity of dust particles, at the induction of the magnetic field 8, 13, and 19 mT, in different regions was measured. For explanation of the experimental results, we developed a simple theoretical model which shows that the direction of the rotation is determined by the radial component of the magnetic field induction.