Free-surface perturbations of collapsing fluid cavities in magnetized target fusion reactors*

Magnetized target fusion reactors achieve fusion conditions by confining plasma in a rotating cavity within a molten lead/lithium working fluid, contained in a cylindrical rotor drum. The cavity is forced to collapse by injecting working fluid through bore holes in the rotor walls. As the cavity collapses, the plasma is compressed and heated rapidly to fusion conditions. For fusion conditions to be attained, it is critical that the free-surface is kept uniform throughout the collapse. This presents a challenge as the interior wall of the rotor, which is perforated with bore holes, causes a non-uniform pressure field, which results in wave-like free-surface disturbances. These disturbances must be minimized as far as possible. Presently, it is not known exactly how the amplitude and shape of the disturbances is affected by the arrangement of rotor bore holes (rotor geometry). In the present work, the influence of the rotor geometry on the free-surface is investigated using a Rankine source panel method. An adjustment is made to account for the periodicity of the bores. The influence of the rotor geometry and initial fill volume of fluid in the rotor is discussed. This work is funded under the NSERC General Fusion/McGill alliance grant.