  A fundamental dynamical constraint -- that fluctuation induced
charge-weighted particle flux must vanish -- can prevent instabilities from
accessing the free energy in the strong gradients characteristic of Transport
Barriers (TBs). Density gradients, when larger than a certain threshold, lead
to a violation of the constraint and emerge as a stabilizing force. This
mechanism, then, broadens the class of configurations (in magnetized plasmas)
where these high confinement states can be formed and sustained. The need for
velocity shear, the conventional agent for TB formation, is obviated. The most
important ramifications of the constraint is to permit a charting out of the
domains conducive to TB formation and hence to optimally confined fusion worthy
states; the detailed investigation is conducted through new analytic methods
and extensive gyrokinetic simulations.
