Models of flux tubes from constrained relaxation

We study the relaxation of a compressible plasma to an equilibrium with flo w. The constraints of conservation of mass, energy, angular momentum, cross -helicity and relative magnetic helicity are imposed. Equilibria correspond ing to the energy extrema while conserving these invariants for parallel fl ows yield three classes of solutions and one of them with an increasing rad ial density profile, relevant to solar flux tubes is presented.