Comment on “Linear stability of a rotating channel flow subjected to a static magnetic field” [Phys. Fluids 34, 054116 (2022)]

Recently, Sengupta and Ghosh [“Linear stability of a rotating channel flow subjected to a static magnetic field,” Phys. Fluids 34, 054116 (2022)] published a linear stability analysis of a pressure-driven channel flow, which is subject to rotation around a spanwise axis and a uniform magnetic field applied in the same direction. Unfortunately, the formulation of the magnetohydrodynamic part of the problem contains an elementary error, which makes the obtained results unphysical. The error is due to unfounded omission of the electric potential contribution in the induced electric current which, thus, does not satisfy the charge conservation.