Slapper detonator

Instead of directly coupling the shock wave from the exploding wire (as the bridgewire does), the expanding plasma from an explosion of a metal foil drives another thin plastic or metal foil called a "flyer" or a "slapper" across a gap, and its high-velocity impact on an explosive (for example, PETN or hexanitrostilbene) then delivers the energy and shock needed to initiate a detonation.

Normally all the slapper's kinetic energy is supplied by the heating (and hence expansion) of the plasma (the former foil) by the current passing through it, though constructions with a "back strap" to further drive the plasma forward by magnetic field also exist.

Usually the construction consists of an explosive booster pellet, against which a disk with a hole in the center is set.

A narrowed section of the metal then explosively vaporizes when a current pulse passes through it, which shears the mylar foil and the plasma ball pushes it through the hole, accelerating it to very high speed.

Slapper detonators are frequently used in modern weapon designs and aerospace technology.

Diagram of a slapper detonator
Diagram of slapper and EBW detonators initiating detonation. (A) Slapper detonator's pellet or flyer impacts a wider area of surface on the explosive output charge, and even though energy is lost to the sides of the area impacted, a cone of explosive is efficiently compressed. (B) EBW detonators only initiate a single point, and energy is lost in all directions, making the energy transfer less efficient.