Small and large versions of the IGNITEX experiment

Small and large versions of the basic IGNITEX ignition experiment have been proposed and analyzed. The basic IGNITEX machine is a high-field, compact, single-turn tokamak with a high plasma current. This tokamak machine uses unconventional magnet and power supply systems that allow the generation of the high magnetic field required for ohmic ignition. The design is based on the assumption that Kaye-Goldston (L-mode) energy confinement time scaling represents adequately the possible confinement degradation induced by alpha particle heating. The basic IGNITEX experiment has high ignition margin for present scaling expressions but it is not designed to ignite under the more pessimistic Goldston scaling. Along these lines, the IGNITEX concept can be divided into two alternatives: (1) a small, minimum-cost machine in which the relevant confinement scaling is the saturated neoalcator (without degradation due to alpha heating) expression, and (2) a larger machine that can handle enough plasma current to produce a reasonable ignition margin with the L-mode Goldston scaling. This larger machine will satisfy the most restrictive requirements.<>