Trapping of a Coulomb ball within an inhomogeneous magnetic field

Abstract

When micrometer sized particles within a complex plasma form void free three-dimensional structures, the resulting organized structures are called Coulomb or Yukawa balls depending on the electric potential. Within a GEC Reference cell at CASPER, a stable Coulomb ball has been created within a complex plasma by magnetic confinement of the MF dust using a rectangular formation of magnets creating an inhomogeneous potential well, in comparison to the usual confinement by the electric potential. The magnetic field responsible for this confinement levitates the dust particles above the RF electrode, leading to the formation of a crystal-like structure. Interaction of this crystal with the ions moving along the magnetic field lines induces a rotational force on the particles, which is dependent on both the plasma power and pressure, as previously. First results on the properties of this Coulomb ball will be presented.