Isolytic burst

From Memory Alpha, the free Star Trek reference.

An isolytic burst is a type of subspace weapon, outlawed by the second Khitomer Accords. The weapon creates a subspace tear that homes in on the target's warp core. Jettisoning and detonating the core may seal the tear, but this does not always work, due to the unpredictable nature of subspace weaponry. The weapon, when fired, has a blue-white tint, and resembles charged plasma in appearance.

Son'a vessels carried isolytic weapons, and used one against the USS Enterprise-E in the Briar Patch in 2375. The Enterprise was able to seal the resultant tear, but lost her warp core in the process. In addition, the explosion caused by the core caused severe damage to the vessel. (Star Trek: Insurrection)