Compact, high-field magnetic mirrors formed by a pair of high-temperature superconducting bulk magnets applicable to plasma/charged particle beam devices

This paper describes a new application of superconducting single-domain bulk magnets to magnetic mirrors. A pair of Sm-Ba-Cu-O bulk magnets, each with a through-hole at the center, was set on the same axis with a separation of ∼48 mm as they attracted each other in order to form a pair of magnetic mirrors used often for plasma confinement. Each magnet occupied only less than one hundredth volume of normal-conducting solenoids to generate the same maximum field at the magnetic throat in the hole. Through the holes was set a discharge glass tube, in which a weakly ionized neon plasma was produced and confined in between the magnets. Spatial optical distribution of the plasma revealed that the mirrors produced a ∼70 times more luminous plasma than no-magnet operation at 1 mA dc discharge current and 0.2 Torr. Thus, the bulk-magnet mirrors have high potential for leading to various types of extremely compact, effective plasma/charged particle beam devices.