Vortex technology has been used in everything from rocket-powered fire extinguishers to Nerf guns, but neither of those things are capable of giving the beat-down to hapless protesters. By giving spinning vortices an electric charge, though, pepper spray can be sent over 150 feet at between 60 and 90 mph.
A vortex gun uses a pressure wave and a carefully designed barrel to fire donut-shaped rings of air that can hold themselves together over long distances. The military (starting with the German military during World War II) has been running experiments with using vortex canons to knock things over, but it's not a particularly efficient or effective way to go. What the gas rings can be used for is transporting other gasses (like pepper spray or tear gas or pesticide) long distances with a decent amount of accuracy, holding their cargo inside the calm center spinning vortex.
A company called Battelle has figured out that by adding some electrical charge to the vortex rings, they can be trained to do all kinds of clever tricks. Any gas inside the ring will immediately stick to anything it hits, whether it's skin or clothing or your eyeballs and mucus membranes. Or, a charged vortex ring could be fired into smoke, transferring its charge to the smoke particles themselves and causing them to seek out grounded surfaces, dispersing them faster than a fan could in a firefighting scenario.
The video below shows the vortex gun in action, along with this shot of what looks like a version of the weapon with a rifle stock. And whether or not these things end up being effective, if you had something as crazy as that pointed at you, you'd probably want to start moving as rapidly as possible in the opposite direction.