Phase- and Wall-Locked Modes Found in a Large Reversed-Field Pinch Machine, TPE-RX

Phase- and wall-locked modes are found to exist in the toroidal pinch experiment called TPE-RX, a large-sized reversed-field pinch machine at the Electrotechnical Laboratory. General characteristics of the locked mode in TPE-RX are similar to those in the reversed-field pinch experiment called RFX, in spite of the difference in the vacuum vessel and the shell system. It is also found that there are certain experimental conditions under which phase-locking disappears. These experimental observations of the locked mode in TPE-RX can provide us with a general understanding of the cause of the locked mode in RFP plasmas.