Theoretical studies of RI-mode on TEXTOR-94 II. Effect of additional channels

It is shown that other effects (than toroidal flow) also contribute to the suppression of turbulence: (a) the ‘knee’ in the ion temperature profile reduces the growth rate of the ITG mode; (b) an increase in ion–ion and electron–ion collisionality due to sudden temperature drop following irradiation by a seeded impurity reduces the growth rate of ITG and ETG modes; (c) an increase in the electron–ion collisionality also shifts the mode frequency of drift resistive ballooning modes in such a way as to reduce the driving terms and contribute to its stabilization; (d) the effect of particle pinch reduces toroidal drive and may even completely stabilize the toroidal ηi mode, leaving only the slab drive; (e) the possible effect of ion-cyclotron resonant-heating on the RI-mode is also studied.