Mach cones and magnetic forces in Saturn's rings

Recently, Mamun, Shukla, and Bingham [2] have claimed that Havnes and his collaborators [1] mistakenly neglected magnetic fields in their work on Mach cones as potentially powerful diagnostics of properties in Saturn's rings. We show that the magnetic force on a charged particle is entirely negligible in comparison to the electric force on the particle in a wave with a wavenumber relevant to the Saturnian Mach cone problem. Havnes et al. [1] were not in error.