Dynamics of a potential barrier formed on the tail of a moving double layer in a collisionless plasma

A negative potential barrier on the low-potential side of a moving double layer gives rise to a current limitation in a collisionless plasma terminated by a positively biased cold collector plate in a Q machine. The double layer is produced in front of the plasma source and moves toward the collector during the limitation. When the double layer arrives at the collector, the barrier dissolves and the current increases, causing a rise in potential along the whole plasma column. The double layer then reforms at the source.