Simon Tam (Sean Maher) holding a Sonic rifle.
An sonic rifle is a non-lethal weapon usually used by law enforcement, that emits a highly-focused, low-pitched sound wave with enough force to drive a big man to the ground. One benefit of the weapon aside from its lack of lethality is the reduced chance of property damage on the Core worlds, since the weapon seems to have no adverse effects on non-living objects.
This rifle was featured in the TV series' episodes "Ariel" and "Trash".