POLOIDAL-OPEN DIVERTOR EXPERIMENTS ON TPE-2M REVERSED-FIELD PINCH

Reversed field pinch configuration with a poloidal-open divertor has been realized quasi-continuously on TPE-2M device with close-fitting shell. Significant increase of liner temperature near the separatrix has been observed, indicating strong heat transport through the separatrix, consistent with calculated last closed flux surface from measured magnetic fields. Spectroscopic measurement has shown that impurities from the limiters and the first wall rapidly increase right after divertor configuration is realized, which are supposed to be due to a short connection length between the separatrix and the wall. Characteristics of resistive kink modes have been found to be similar to those without divertor. Apppearance of local magnetic fluctuations near separatrix, however, have been observed by the onset of divertor fields, but not to grow to the disruption.