An ion pulse was a type of warhead. An ion pulse was installed on Naboo, following the Trade Federation's invasion of the planet in 32 BBY. It disabled any threat that was outside the Theed Royal Palace upon its activation. Its installation began during the reign of Queen Padmé Amidala and continued under the reign of Queen Réillata, though it was publicly opposed by Captain Quarsh Panaka, who wanted more robust defenses. Quarsh's opposition to the pulse resulted in a damaged relationship with Amidala and politicians who supported it, which by 28 BBY had never fully recovered. It also put a strain on his marriage, as his wife Mariek was also in favor of the pulse.
Ion pulses could also be triggered without a warhead, as R2-D2 caused an ion pulse to occur at Sunspot Prison between 0 and 1 ABY using the facility's own systems, knocking out power.
Following the Battle of Endor and the death of Emperor Palpatine in 4 ABY, Operation: Cinder, a contingency order issued posthumously by Palpatine to render worlds inhospitable in the event of his death, was carried out on Naboo. During the ensuing battle, the pulse was activated by the Rebel Alliance, disabling all Imperial weapons and forcing them to surrender to the rebel forces present.