Magnetized electron emission from a small spherical dust grain in fusion related plasmas

The effect of magnetic field on the electron emission yield from a small spherical dust grain immersed in a plasma is investigated. It is demonstrated that, due to their gyromotion, some electrons can be promptly recollected on the grain's surface, which can reduce the emitted electron flux. The consequences are discussed mainly in the context of fusion-related applications, where the dust floating potential can be significantly reduced when positive while the dust lifetime remains weakly affected. In particular, we suggest that this effect should be included in the codes used to model the dust transport in tokamaks.