LARGE-AMPLITUDE OSCILLATIONS OF SOFT X-RAYS IN A HIGH-CURRENT DENSITYPLASMA ON TPE-1RM15 REVERSED-FIELD PINCH

In the high current density plasma on TPE-1RM15 reversed field pinch, large-amplitude oscillations with m = 0, n = 0 are observed in soft x- ray (SXR) emission for a wide range of theta values, even at low-theta (theta < 1.55) discharges. Another small-amplitude oscillation with m = 1 is observed quasicontinuously for almost all the discharge. The b urst of high-energy soft x-rays is observed in the channels of the SBD array looking at the electron drift side of a metal limiter and seems to correlate with the crash of the large-amplitude oscillation. This SXR burst indicates the existence of energetic electrons flowing along the field lines near the plasma surface in the dynamo phase. These la rge-amplitude SXR oscillations are mainly due to the variations in the electron temperature and are roughly in antiphase with the oscillatio n of ion temperature.