Fluid description of electron temperature gradient driven drift modes

The electron temperature gradient (ETG) driven drift mode is studied using an advanced fluid model retaining effects of nonadiabatic ions, Debye shiel ding and the electron diamagnetic heat flow. The derived eigenmode equation is solved analytically in the strong ballooning limit. Both the toroidal a nd the slab branch of the ETG mode are included and the fluid growth rates are compared with gyrokinetic results. The role of nonadiabatic ion respons e is found to have a stabilizing effect on ETG-mode in the lower-hybrid reg ime. Strong stabilization is also found due to Debye shielding effect for l ambda (2)(De)/rho (2)(e)>1. In particular, it is shown that nonadiabatic io n response can result in inward flows of particles for peaked density profi les. (C) 2001 American Institute of Physics.