The Long Remembered Thunder

Laumer, Keith. "The Long Remembered Thunder." Worlds of Tomorrow April 1963. Coll. Nine by Laumer. Rpt. The Best Science fiction from Worlds of Tomorrow. Frederik Pohl, ed. New York: Galaxy, 1964.

Features a machine that can focus thoughts, used as a weapon to keep an alien invasion force from crossing a portal into our world. For Psi-powers and machinery, cf. KL's "End as a Hero". (RDE, 07/05/01)