Comment on “Instability of the Shukla mode in a dusty plasma containing equilibrium density and magnetic field inhomogeneities” [Phys. Plasmas 11, 1732 (2004)] and “New resonance and cut-off for low-frequency electromagnetic waves in dusty magnetoplasmas” [Phys. Plasmas 11, 2307 (2004)]

It is shown that the oscillation named by Shukla as the “Shukla mode” is well known in the plasma physics literature as the magnetic drift wave. In addition, the instability of these modes in a cold plasma as claimed by Shukla et al. [Phys. Plasmas 11, 1732 (2004)] does not exist and is due to a mathematical error in their analysis. Also the “new” resonance and new cutoff frequencies claimed by Shukla et al. and Mamum et al. [Phys Plasmas 11, 2307 (2004)] have been known in the published literature for decades. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]