Ohmic and alpha heating in the high-field IGNITEX tokamak

Summary Form only given, as follows. The fusion ignition experiment IGNITEX will utilize a single-turn coil tokamak to produce and control ignited plasmas for scientific study., The special design characteristics of the IGNITEX device should permit a toroidal field on a plasma axis of 20 T and plasma currents of 12 MA during a 5 s flat top (about 10 energy confinement times). The pulse length is extended to a total of 10 s by precooling the magnet structure to liquid nitrogen temperature. During the initial current and field ramping of the experiment, ohmic heating and bremsstrahlung radiation emission are dominant. When ignition conditions are attained, alpha heating and cyclotron radiation emission become dominant. A path to the high-temperature, energy-gain region of the (n, T) diagram is opened by the alpha particle heating. Thermal damping at ignition is produced by electron cyclotron emission. The thermal wall loading (assuming uniform deposition) is 3 MW/m/sup 2/ at the time of ignition. Ignition far from marginal stability and disruptive regimes is possible. Plasma-wall stabilization makes high beta operation feasible. Good equilibrium configurations with and without separatrix can be produced, as well as null field regions for plasma breakdown. High alpha-particle containment is possible because of the small alpha gyroradius and the large plasma current.<
>