Coulomb structures of charged macroparticles in static magnetic traps at cryogenic temperatures

Electrically charged (up to 10⁷ e) macroscopic superconducting particles with sizes in the micrometer range confined in a static magnetic trap in liquid nitrogen and in nitrogen vapor at temperatures of 77–91 K are observed experimentally. The macroparticles with sizes up to 60 μm levitate in a nonuniform static magnetic field B ~ 2500 G. The formation of strongly correlated structures comprising as many as ~10³ particles is reported. The average particle distance in these structures amounts to 475 μm. The coupling parameter and the Lindemann parameter of these structures are estimated to be ~10⁷ and ~0.03, respectively, which is characteristic of strongly correlated crystalline or glasslike structures.