In inviscid magnetostrophic balance within an impenetrable axisymmetric container, with no azimuthal buoyancy or external mechanical torque, the cylindrically integrated Lorentz force density must vanish on every cylinder coaxial with rotation. The azimuthal pressure derivative integrates to zero, and the cylindrical Coriolis integral is proportional to net radial flux, zero by incompressibility and impermeability. Multiplying by cylinder area and lever arm gives the equivalent zero-torque form. This rotating-fluid condition is distinct from magnetic-helicity relaxation to a force-free plasma state. Its original primary source is Taylor's 1963 rotating-fluid paper.
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