Stratified shearing valves

With APM one can create valves that can open and close very fast.

Methods

For maximal switching speed one can use interleaved shells that move into opposite directions (using infinitesimal bearings?) and have gaps that match up only at certain times. The timespan relation betwen open and closed states is heavily restricted.

For lower but still high switching speeds platelets that when moved completely balance out linear and angular momentum can be used.

Applications

One speculative application of such valves is inertial fusion. Where it could be used to let through an accelerated fuel pellet of hydrogen and close the "door" right behind to protect the acceleration area from radiation that is backscattered electrons protons and generated gamma rays (as far as possibel).