Toroidal microinstability studies of high-temperature tokamaks

Results from comprehensive kinetic microinstability calculations are presented, showing the effects of toroidicity on the ion temperature gradient mode and its relationship to the trapped-electron mode in high-temperature tokamak plasmas. The corresponding particle and energy fluxes have also been computed. It is found that, although drift-type microinstabilities persist over a wide range of values of the ion temperature gradient parameter ηi≡(d ln Ti/dr)/ (d ln ni/dr), the characteristic features of the dominant mode are those of the ηi-type instability when ηi>ηic∼1.2–1.4 and of the trapped-electron mode when ηi<ηic.