Low mass wall-confined discharge for light ion beam transport

Summary form only given. A low-mass version of the wall-confined discharge transport channel employing 250-μm-wall. 2.5-cm-diameter spiral-wound Kapton tubes has been developed. These tubes weigh only 30 g/m and are free-standing. The return current is carried by copper tape: vapor-deposited aluminum could be used in an eventual reactor. Discharges up to 2.5 m in length have been created with the Kapton surviving intact. Electrical monitors have been used to study the breakdown process and the resulting radial current distribution in the channel as a function of length and fill pressure. A uniform current distribution is established fairly early in the discharge current cycle, and for pressures above 2 T this distribution persists until about peak current (800 ns), after which pinching takes place. Preliminary Gamble II experiments have shown efficient ion beam transport over 1 m