Relaxation of collisional magnetically confined plasmas to mechanical equilibria

The relaxation of magnetically confined plasmas in a toroidal geometry is analyzed. From the equations for the Hermitian moments, we show how the system relaxes towards the mechanical equilibrium. In the space of the parallel generalized frictions, after fast transients, the evolution of collisional magnetically confined plasmas is such that the projections of the evolution equations for the parallel generalized frictions and the shortest path on the Hermitian moments coincide. For spatially-extended systems, a similar result is valid for the evolution of the thermodynamic mode (i.e., the mode with wave-number k = 0). The expression for the affine connection of the space covered by the generalized frictions, close to mechanical equilibria, is also obtained. The knowledge of the components of the affine connection is a fundamental prerequisite for the construction of the (nonlinear) closure theory on transport processes (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)