Generalized gyroviscous force and its effect on the momentum balance equation

The perturbed nonlinear gyroviscous force is calculated by solving the stress tensor evolution equation. The result shows that del x the gyroviscous stress tensor mostly cancels the diamagnetic convective term. This formula generalizes the usual, widely used gyroviscous cancellation in which the del x the gyroviscous stress tensor cancels mostly the total time derivative of the diamagnetic flow to include temperature variations and a perturbed stress tensor drift. It is proved that when temperature variations are neglected, the new formula reduces to the conventional form. When the temperature variations are considered, the new formula is much simpler and more rigorous than the conventional one. A new polarization drift formula deduced from the new gyroviscous force is also derived.