A comment on the stability of magnetic wind-driving accretion discs

In a recent paper, Lubow, Papaloizou & Pringle argued that magnetized accretion discs in which the inward radial velocity at each radius is determined by angular momentum loss through a centrifugally driven wind from the disc surfaces, with the total mass outflow rate remaining small in comparison with the accretion rate, are probably unstable. We point out several difficulties with the analysis presented in that paper: in particular, we show that the basic argument of the paper does not hold for magnetic disc-wind models of the type considered by Wardle & Königl, and hence that its general conclusion regarding the stability of magnetic wind-driving accretion discs is invalid. Although the stability of such disc configurations is still an open question, they appear to be immune to the most disruptive types of instability.