Psi emitter

The psi emitter, formally the Transplanar Psionic Waveform Emitter, was a piece of terran technology with the ability to lure the zerg to its signal. Researchers running the Confederate ghost program found that the zerg were attuned to the alpha brain waves of ghosts, and the emitter broadcast a ghost's neural imprint at far greater magnitude, reaching across worlds at ranges of ten to twenty-five light years. The device became one of the most consequential weapons in the history of the Koprulu sector, the instrument by which Arcturus Mengsk destroyed the Terran Confederacy and condemned billions on Tarsonis to the Swarm.

Function#

Psi emitters were portable machines that broadcast the neural imprint of a ghost, exploiting the fact that the zerg were attuned to the alpha waves of psychic terrans. Activation required a ghost or other psychic. Once running, an emitter could reach across worlds at a range of roughly ten to twenty-five light years, and numerous emitters in the same area amplified the overall effect. An emitter could be attuned to attract particular zerg breeds to a chosen location.

The zerg drawn by an emitter abandoned all battle caution and positional awareness, crowding over themselves and pushing through enemy lines to reach the source of the signal. This made the device both a weapon and, in other hands, a shield. The Terran Dominion often used emitters to draw zerg attacks away from civilian population centers. By the time of the Defenders of Man insurgency, an emitter had been designed that could be delivered remotely through atmospheric insertion, made possible through Moebius Foundation technology.

Mar Sara and the rise of the Swarm#

The Terran Confederacy intended to use psi emitters to lure the zerg into isolated containment areas, planning to set the Swarm against its rivals and then be hailed as heroes for destroying the very threat it had summoned. When the emitters were activated, however, they brought the entire Swarm to the Koprulu sector rather than the manageable numbers the Confederacy had hoped for.

One such emitter on Mar Sara came into the hands of Sons of Korhal engineer Merdith Jernic. She was captured by the abandoned 417th Confederate Marine Platoon and questioned by its commander, who suspected her account of how she had acquired the device. The platoon eventually activated the emitter to draw the zerg toward a prepared position and away from the major cities, buying time for the Sons of Korhal to evacuate Mar Sara City. The platoon was wiped out. Before leaving the world, Jim Raynor, newly recruited to the Sons of Korhal, led a raid on the Jacobs Installation to retrieve Confederate designs and schematics.

Antiga Prime and Tarsonis#

When headquarters completed its analysis of the recovered data, Arcturus Mengsk had his second in command, the ghost Sarah Kerrigan, explain that the discs contained designs for a psi emitter. On Antiga Prime, Mengsk had Kerrigan plant an emitter within the base camp of a large Confederate strike force, and the zerg descended on the unsuspecting troops and annihilated them.

Mengsk's forces then traveled to the Confederate capital of Tarsonis and had Alpha Squadron plant emitters there, over the strong objections of Jim Raynor and Sarah Kerrigan. The combined power of the emitters lured billions of zerg to the world, and the Swarm overran the Confederacy's defenses and laid waste to its cities and industrial centers. The act broke the Confederacy and cleared the path for Mengsk to declare the Terran Dominion.

Later use#

During the Brood War, Mengsk, by then Emperor of the Dominion, was deposed by the United Earth Directorate, which assembled a psi disrupter on Braxis that crippled Kerrigan's control over her zerg. Mengsk's emitters became essential to breaking the disrupter. After Raynor's Raiders destroyed the disrupter's primary power generator, an emitter carried by one of Mengsk's SCVs drew the attention of nearby renegade zerg, letting Kerrigan seize direct control of them and destroy the device.

In the Second Great War, Raynor's Raiders attacked a Dominion salvage operation on Tarsonis and made off with Adjutant 23-46, which held the record of the order to use the emitters. Decrypted, the adjutant exposed Mengsk's guilt, and the Raiders broadcast it through the captured UNN Studios to weaken his rule. During the End War, Alexei Stukov used psi emitters to direct his infested terran forces. Afterward, the Defenders of Man under General Carolina Davis planted emitters on scattered Dominion colonies to draw feral zerg and then arrive as saviors, hoping to discredit Emperor Valerian Mengsk. Nova Terra and another ghost were misled into planting these devices, and Nova later worked to expose and stop the scheme, vowing to prevent a planned strike on Tyrador IX.