Improved plasma performance through novel boundary control techniques

It is shown that the separatrix of a tokamak plasma can be exhausted through the TF coils, without unacceptable field ripple at the plasma. Advantages of this include greatly reducing heat loads on the divertor, improving impurity content and ash exhaust, enabling power exhaust in regimes with more favourable confinement, and improving prospects for high availability and high wall loading in a fusion reactor. Furthermore, new confinement regimes become possible with profoundly reduced recycling, which can greatly improved energy confinement. Within the existing experimental and theoretical understanding of tokamak core transport, this modification of the edge boundary could enable energy confinement on the order of the neoclassical particle confinement time. (author)