The importance of the E x B Bow shear in various enhanced confinement
regimes is discussed in terms of the turbulence suppression criterion
in general toroidal geometry. This criterion is then further generaliz
ed to include the poloidal angle dependence of the equilibrium electro
static potential. The implication of the recently observed in-out asym
metry in the fluctuation behaviour in DIII-D VH-mode is discussed.