Repulsors
Repulsors are high-density muon beams.
They were created by Tony Stark for use in the first Iron Man Armour, as both a weapons and flight stabilisation system.
Iron Man Suits use repulsors embedded in the hands and feet of the suits as the stabilisation and steering systems. Some suits, especially those used by Tony Stark, also have a repulsor in the chest of the suit, for use as a weapon.