= Single-azimuthal-mode current-driven instability threshold
{title2=$|m|=1,\quad m\delta>\tfrac12$}
In the <uniform-current rotating magnetohydrodynamic wave dispersion>, exponential growth requires $J^2(2m\delta-m^2)/(4\mu_0\rho)>\delta^2\Omega^2$. For integer $m$ and $|\delta|<1$ this is possible only for $|m|=1$ and $m\delta>1/2$. Positive and negative $m$ branches are related by <complex conjugation>. The equality case is a repeated frequency and requires separate analysis of possible algebraic growth.
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