10 Hz deuterium pellet injector for 1000 s continuous fuelling

A new deuterium pellet injector for plasma fuelling in a steady state mode has been developed. A technique for continuous solid deuterium ice extrusion by a screw extruder is suggested for the production of an unlimited number of pellets. A cylindrical rod of 2 mm in diameter and over 100 m in length made from transparent solid deuterium ice was extruded continuously for over 3000 s at the temperature of 16 K and 35 mm/s speed. Over 25000 deuterium pellets of 2 mm in size were produced by the injector in the steady state mode at the rates from 1 to 14 Hz and accelerated to 600-700 m/s. Three series of 12103, 12584 and 14600 deuterium pellets were continuously injected at 10 Hz with the reliabilities of 99.2, 98.8 and 99.5%, respectively. All pellets in flight were recorded by a CCD-camera and a computer and were found to be intact. (author)