Differential Dust Disk Rotation in a Complex Plasma with Magnetic Field

Abstract

Collective motion of charged dust particles, levitated in a disk and a ring that forms in cylindrical electrodeless RF plasma with an axial magnetic field, was investigated experimentally. The measured angular velocities of the disk and the ring are less than 10 rad/s and less than 8 rad/s, respectively. We found that the angular velocity strongly depends on the gas pressure and the strength of the magnetic field while the RF power does not significantly influence the rotation of the dust structure.

Tempest in a glass tube: A helical vortex formation in a complex plasma

“…A rotation of a dust cloud with a magnetic field on the ground is also observed by many researchers (for examples, Konopka et al 2000;Karasev et al 2006;Pilch et al 2008;Reichstein et al 2010). In these experiments, it is pointed out that the importance of the ion drag force is a driving force of the dust cloud rotation.…”

“…B . 1.5 kG and it is often observed that the dust particles distribute with fine structures (Saitou et al 2014). The structure depends on the strength of the magnetic field and, typically, consists of an outer ring and an inner disk.…”

“…In our previous research work, we found that dust particles form two dimensional and three dimensional structures in a cylindrical complex plasma generated by rf discharge with a strong magnetic field (Saitou and Ishihara 2013;Saitou et al 2014). These structures have unique characteristics.…”

Plasma Physics Researches in Asia Pacific Region

“…In an interesting basic laboratory experiment reported in [80], positively charged dust particles were trapped about 0.3 mm beneath a thin liquid He (LHe) layer and shown to create a stable bound state with electrons over the LHe surface. In another basic experiment [81] a layer of levitated dust particles was subjected to a non-uniform magnetic field causing it to rotate in a differential manner and to also generate spiral arm structures. These results could throw some light on the behaviour of astrophysical dust clouds that display similar behaviour.…”