A review is given of the Extrap concept and its possibilities of being extrapolated to a full-scale fusion reactor. The toroidal Extrap configuration consists of a Z-pinch being immersed in an octupole field generated by currents in a set of ring shaped external conductors. This configuration satisfies the equilibrium conditions of an optimized fusion reactor, in having closed field lines, closed particle drift orbits, fully axisymmetric geometry, no toroidal magnetic field, and a high plasma beta value. Small scale linear and toroidal experiments have demonstrated macroscopic stability, at least for a number theta-i approximately equal to 4 of ion Larmor radii being contained within the pinch radius. The stability appears to be explained by a combination of MHD like and kinetic effects in Extrap geometry. For extrapolation to a full-scale reactor further experimental and theoretical analysis is needed for more reactor relevant conditions, on such questions as the stability for theta-i approximately equal to 20 contained ion Larmor radii, plasma neutral gas interaction, anomalous transport and impurity radiation losses.
Bibliographic Reference: WRITE TO THE DEPARTMENT OF PLASMA PHYSICS AND FUSION RESEARCH, ROYAL INSTITUTE OF TECHNOLOGY, S-100 44 STOCKHOLM (SWEDEN), MENTIONING REPORT TRITA-PFU-87-02, 1987
Record Number: 1989126025701 / Last updated on: 1989-01-01
Available languages: en