Stability of a closed-line Scyllac configuration

A stability analysis against m = 1 modes is presented for a closed-line Scyllac configuration. The configuration consists basically of a large θ-pinch field and moderate-size ℓ = +1 and ℓ = −1 fields with exactly equal amplitudes. It was originally hoped that the ℓ = ±1 system would have more favourable stability properties than the pure ℓ = 1 Scyllac configuration. The calculations show that this is not the case, and that, indeed, the ℓ = ±1 system is far more unstable.