Damping of the motion of electron-hole drops in magnetic fields

We report the observation of an unexpectedly large damping caused by small transverse magnetic fields on the motion of electron-hole drops (EHD) in germanium. Possible causes for the damping are discussed, and we show that the observations are consistent with a mechanism closely related to magnetohydrodynamic damping. Such effects are anomalously large in the EHD system due to its unusually large ratio of electrical conductivity to mass density. © 1977 Società Italiana di Fisica.