In this paper, a theory of toroidal ion temperature gradient-driven weak turbulence near the threshold is presented. The model considers gyrokinetic ions and adiabatic electrons in toroidal geometry. The linear theory considers modes generally not considered in toroidal theories. The instability is saturated via nonlinear ion resonance, andit is shown that this nonlinear process transfers energy directly from the waves to the ion distribution function, and does not conserve wave energy.
