Drift-mode stability analysis for the Tandem mirror

Drift-mode stability analysis for the Tandem Mirror Experiment is formulated assuming MHD-stability from magnetic field curvature and plasma rotation. The self-consistent field equations describe two potentially unstable drift modes. For k || ∼ 2π/L c , where L c is the length of the central cell, the electron drift wave occurs with ω ∼ ω *e S (b, η i ) ∼ k || v A with a radial localization to the region of maximum electron diamagnetic drift frequency ω *e . For flute-like axial modes, the ion drift wave ω ∼ ω *i > k || v A occurs. The ion drift mode is less radially localized and extends to high frequencies for large k ⊥ ρ i . Stability conditions as a function of η i , η e , β and T i /T e are developed for the drift modes including the guiding-centre drifts and bounce frequency resonances with the electrons.