Antimatter charge

An antimatter charge was a type of explosive deterrent antimatter weapon used aboard Federation starships during the 23rd century and Pakled starships in the 24th century.

In 2269, after the USS Enterprise (NCC-1701) became engulfed by an unidentified cosmic cloud, the ship was approached by several objects composed of highly charged gaseous antimatter, which caused a considerable strain on the Enterprise's shields.

In attempt to lessen the objects drain on the shields, James Kirk ordered Montgomery Scott to "prepare the shields for an antimatter charge" that, when fired, temporarily pushed the objects away from the Enterprise. This did not prove to be enough, as the objects came back towards the Enterprise, causing Kirk to order engineering to "double the charge," and finally removing the objects from the shields and their threat on the ship. 

In 2365, Geordi La Forge improvised and created photon torpedoes by increasing antimatter charges of the Pakled ship Mondor. Prior to the modifications, the charges were considered as limited armaments. They were not even powerful enough to blow up asteroids, and did not present any danger to the USS Enterprise (NCC-1701-D).