What is "pasotron"

A Plasma-assisted slow-wave oscillator (Pasotron) is a directed energy device that produces high-power, long-pulse microwave energy. Because the device does not require any externally produced magnetic fields to confine the electron beam used to generate the microwaves, it can be constructed to be smaller and lighter than other high-power microwave sources. In the early 1990s, pasotrons began to be considered as a possible directed energy weapon applicable to missile defense, radio jamming and other military uses. 1