Transition to the H-mode by energetic electrons

The effect of electron loss due to the toroidal ripple on the H-mode transition is studied. When energetic electrons exist in tokamaks, for example in the case of electron heating by lower hybrid (LH) waves, the edge electric field may exhibit bifurcation to more positive values. In this state, both the electron loss and the ion loss (such as direct orbit loss) are reduced. The criterion for the transition is derived. Comparison with the H-mode in JT-60 LH plasma shows qualitative agreement