Twisted-Pair Plasma Current Rogowski Coil

A Rogowski-style current sensor includes a twisted pair of wires or cables formed into a coil. A second coil formed from another pair of wires or cables, twisted in the opposite direction, may be placed alongside, but not necessarily immediately adjacent to, the first coil, and the signals from each twisted pair may be added or subtracted to measure the enclosed current or a diamagnetism. When the current to be measured is a plasma current in a tokamak, the current sensor may be placed behind shielding tiles on the inner wall of a vacuum vessel that contains the plasma. Another current sensor may be placed on an external wall of the vacuum vessel, and the outputs subtracted to measure a current flowing through only the vessel itself.