First results from TEXTOR

Abstract

The paper summarizes the main results obtained during the first six months of experimental work on TEXTOR with ohmically heated plasmas. The machine(R = 175 cm; a = 45-50 cm) was operated at wall temperatures up to 303 ^oC with hydrogen gas, a toroidal field of 2 T and a maximum plasma current of 500 kA, yielding central electron temperatures of 1.2 keV, maximum line-averaged densities of 4 x 10¹³ cm^-3 and discharge durations of up to 2.7 sec (for Ip≤340 kA). Besides providing long-lasting reproducible plasmas for forthcoming plasma wall interaction research, the following tasks were accomplished: (1) control of low Z impurities by effective wall cleaning and conditioning; (2) accurate plasma positioning for extended pulse durations; (3) determination of the current density distribution by way of Faraday rotation measurements; (4) investigation of plasma limiter interaction including spectroscopic determination of released neutral particle fluxes and measurement of the power density distribution in the scrape-off layer by infrared-thermography.