AbstractThe EVOLVE (EVaporation Of Lithium and Vapor Extraction) concept is a recently proposed liquid metal blanket. In EVOLVE a significant fraction of the fusion power is released in the liquid by nuclear volumetric heating and extracted from the fluid though a number of thin vapor channels by evaporation of lithium. The flow in the liquid phase under the influence of a strong, uniform, horizontal magnetic field is analyzed and the shape of vapor channel cross sections is determined. Vapor cross sections remain circular for strong surface tension but they may become highly elongated along magnetic field lines for strong magnetic fields.