Threshold conditions for amplified spontaneous emission of x radiation

Threshold conditions for obtaining amplified spontaneous emission of x radiation, inclusive of strong line broadening and loss processes, are presented and evaluated for the case of pumping by ion-atom-ion-ion collisions. Quasistatic as well as pulsed operation of such x-ray lasers is seen to be realizable in terms of currently operative plasma systems. © 1974 The American Physical Society.