Magaboomvroom

Reading about rotating detonation engines it occurred to me that there must be enormous friction losses in the chamber. So the idea is to use magnetic, rather than physical, containment. An additional benefit would be the ability to easily shrink or expand the volume, and change the shape of the chamber for best efficiency in various flight profiles and external/internal pressure combinations. For example letting the engine compensate for reduced LOX pressure when you're near to running out instead of using a heavy and power-sapping pump, or going from atmospheric to space flight.