MARAUDER (Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation) was a United States Air Force Research Laboratory project concerning the development of a coaxial plasma railgun.
Such a system could be used for “hypervelocity projectiles,” x-ray production, and electrical power amplification.
The stated goals of the program included studying the “formation, compression, and acceleration of magnetized plasma rings.”[2] Specifically, the objective of the program was the acceleration of a toroid of 0.5 to 2 milligrams (0.0077 to 0.0309 gr) plasma to a kinetic energy level on the order of megajoules using a 5-10 MJ coaxial gun design.
It utilized the Shiva Star capacitor bank to satisfy the large energy requirements that were needed.
Doughnut-shaped rings of plasma and balls of lightning caused "extreme mechanical and thermal shock" when hitting their target, as well as producing a pulse of electromagnetic radiation that could scramble electronics.