Free surface perturbations of collapsing fluid cavities in magnetized target fusion machines

Magnetized target fusion machines achieve fusion by magnetically confining plasma in a blanket (liner) of molten alloy fluid, formed by spinning the fluid in a cylindrical rotor drum to create a vortex and central cavity. The cavity, containing the plasma, is forced to collapse by injecting fluid into the rotor through an array of bore holes in the rotor walls. As the cavity collapses, the magnetic field, and plasma which it confines, are rapidly compressed heating the plasma to fusion conditions.

For fusion to be attained, it is critical that the free surface of the cavity 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. Presently, it is not known exactly how the amplitude and shape of the disturbances are 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 experimentally and numerically using a Rankine source panel method. The results are validated using commercial CFD. The influence of the rotor geometry and initial fill volume of fluid in the rotor are discussed.