Experimental Demonstration of Acceleration and Focusing of Magnetically Confined Plasma Rings

We have demonstrated acceleration of magnetically confined plasma rings in a coaxial accelerator, with acceleration of 0.02-mg ring masses to 1.4×{}10⁸ cm/sec at {≥} 30% efficiency. In some cases low-mass rings have reached a velocity of 2.5×{}10⁸ cm/sec. When the accelerated rings translate into conical electrodes, we have observed focusing of rings by a factor of {~}3 in radius, with a factor of {≥} 4 magnetic field amplification. A reasonably complete accounting of ring mass, momentum, and energy confirms the basic concept of acceleration of stable, well-confined magnetized plasma rings.