PUMP LIMITER EXPERIMENT IN THE TFR TOKAMAK
Pump limiter experiments are carried out in the TFR Tokamak. The first TFR pump limiter is located in the outer part of the torus, its double-throat head is made of graphite tiles, the neutralizer plates are made of stainless steel, and it is pumped by a 3500 l s**-1 titanium sublimation pump. The first attempts showed that the exhaust efficiency epsilON of this pump limiter was low (1.5% of the total plasma particle efflux). To improve on these results, a new limiter head with a single longer throat has been built. The particles were better trapped and the pumping achieved an important decrease of the recycling coefficient. Geometric features and also the highly non linear regime of pressure in the pump limiter as a function of the density at the entrance slot could explain the increase by a factor 3.5 of the exhaust efficiency (epsilON = 5%). Ion temperatures of the order of a few eV have been deduced from Doppler broadening measurements at the neutralizer plate of the pump limiter.
Bibliographic Reference: JOURNAL OF NUCLEAR MATERIALS, NOS. 145-147 (1987), PP. 819-824
Record Number: 1989126015700 / Last updated on: 1989-03-01
Available languages: en