International audienceCollective light scattering (CLS) has been recently extended to the observation of Hall effect thruster plasmas. A better understanding of the physics of Hall thrusters is key to improving thruster operation and lifetimes. In particular, the origins of thruster phenomena such as anomalous electron transport need to be determined. A high-performance CLS diagnostic has therefore been developed for identifying and measuring electron density fluctuations in the thruster, at millimetric length scales and MHz frequencies. Such modes are believed to play a role in anomalous transport, and experiments so far performed have provided information on their dispersion relations, amplitude and directivity. This work describes the technical aspects of the optical bench and the range of accessible experiments (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim