Banana fluxes in the plateau regime for a nonaxisymmetrically confined plasma

The banana (or banana-plateau) fluxes, related to the generalized stresses 〈B⋅∇⋅πα(n)〉, 〈BT⋅∇⋅πα(n)〉 have been determined in the plateau regime, for a plasma confined by a toroidal magnetic field of arbitrary geometry. The complete set of transport coefficients for both the ‘‘parallel’’ (ambipolar) and ‘‘toroidal’’ (nonambipolar) banana fluxes was obtained in the 13-moment (13M) approximation, going beyond the previously known expressions in the nonaxisymmetric case. The main emphasis is laid on the structure of the transport matrix and of its coefficients. It is shown that the Onsager symmetry of this matrix partly breaks down (for the mixed electron–ion coefficients) in a nonaxisymmetrically confined plasma.