Comment on “Effects of electron temperature anisotropy on proton mirror instability evolution” by Ahmadi et al. (2016)

In a recent paper, Ahmadi et al. (2016) analyze the effect of electron temperature anisotropy on proton mirror instability. They find that the electron whistler instability grows faster and consumes all the available electron free energy so that no anisotropy is left to fuel the proton mirror mode growth. In this comment we present both observational and theoretical arguments about why we think this is incorrect.