Results from the reversed field pinch experiment on TPE-1RM15 with a programmed vertical field

The TPE-1RM15 is a new moderate size machine with R = 0.7 m and a = 0.135 m, operating as a Reversed Field Pinch (RFP) at a current of up to 200 kA and a pulse duration of 8 ms. A DC vertical field, Bvdc, is used to centre the plasma toroidal equilibrium in a thick shell, and plasma formation is assisted by a pulse cancellation field produced by coils inside the shell. During the flat-top phase at Ip = 135 kA, there is an optimum in Bvdc equal to 7.7 mT, and Te0 ∼ 600 eV and ne0 ∼ 2x1019m-3 are obtained by Thomson scattering. The temperature is confirmed by analysis of the soft-X-ray spectrum measured with a SiLi detector. In these conditions the helicity resistivity on axis shows an anomaly factor of four, Vloop = 30 V, βp ∼ 10%, τE ∼ 0.2 ms and 1/N ∼ 25x10-14A·m. The DC vertical field is varied over a wide range and Te0 ∼ 400 eV at Bvdc = 0. (author)