Abstract
The self-stabilization of the two-ion-beam instability due to microturbulent ion heating has been measured in a plasma with variable temperature ratio (2.0<TeTi<10.0). When the plasma is unstable, excited ion waves and background microturbulence are observed to grow, saturate, and damp, in conjunction with ion heating. When the plasma is stable, no ion heating is observed. The ion heating e-folding length is 500λde. This heating may occur in the formation of collisionless shocks.