Powerful pulsed laser application in setups for magnetic fusion energy

Abstract

Summary form only given. To build a commercial nuclear fusion reactor based on the tokamak or stellarator concept requires the solution of several research and engineering problems. It is necessary to find the optimum regimes with the best plasma confinement to reduce the size of future reactors and its cost. By creating plasma-magnetic configuration with a negative magnetic shear and other active methods of plasma control, the global time of plasma energy confinement has been substantially increased. It seems necessary to provide a continuous and reliable operation of the reactor, completely excluding occurrence of the most hazardous hydrodynamical instabilities causing plasma disruptions. To, solve the problems mentioned, it is useful to consider new and promising technologies such as the use of powerful pulsed CO/sub 2/-lasers. The application of pulsed CO/sub 2/-lasers for heating the plasma confined by a magnetic field was discussed in the early 70's (Dawson et al., 1971). The concept of electron heating in the electron cyclotron heating mode has proved to be inefficient as it has required extremely high magnetic fields. Recently, ideas of using lasers in tokamaks and stellarators have received a significant effort on the basis of another approach, i.e. laser pulse radiation of fuel pellets injected into the setup chamber (Nastoyashchii, 1996). Summary form only given. The approach enables solving a number of problems important for plasma confinement and suppressing several dangerous instabilities, including: (1) pellet acceleration up to velocities of order of 20 km/s and above, which are required for injection in the tokamak (stellarator) reactor; (2) non-inductive current-drive to sustain the steady-state operations of device including the control of the periphery currents; (3) the creation of stationary controlled plasma-magnetic configurations with a B minimum and raised plasma pressure, etc. An important property of laser applications is a local control of plasma and magnetic field parameters which permits to realize the most optimal plasma-magnetic configuration with high beta and improved confinement.