You might have heard of the most popular fusion design, tokamaks like JET (Joint European Torus) and ITER (International Thermonuclear Experimental Reactor), devices that look like giant donuts and utilize giant magnets to confine and accelerate plasma. Or perhaps you've heard of NIF's (National Ignition Facility) laser initiated approach which counts on a massive 192 barrel laser cannon to focus all its energy on a tiny pellet in order to compress it to such a degree as to achieve ignition. Those two approaches have received the most attention and as a result have sucked up most of fusion's funding in the last few decades. They do look promising and are worth every penny spent but a variety of new approaches has been picking up steam which too are deserving of a much closer look and thus the funds to do so.
Nature digs into some of them with this excellent article that shines a bit of light on the secretive start-ups that claim to have found the answer to our energy woes. There's Tri Alpha's linear design trying to get things going by having 2 directly opposite plasma cannons fire at each other in sync as well as Helion Energy's somewhat similar colliding-beam reactor and last but not least they also talk a bit about General Fusion's approach which hopes to literally hammer their plasma into obedience.
If you think that's an exhaustive listing, you'd be wrong. Another big one is Lawrenceville Plasma Physics's Focus Fusion idea but there's also various teams hoping to work on different types of stellarators as well as the so called triple-threat methods. So many avenues worth exploring yet so few funds to do so. Luckily the private sector is chipping in a bit because else these would all have been shot down before even having had a chance of making it to the door. The fact that VCs, including some really big names, are investing in these should raise eyebrows as they don't typically start pumping money into something unless the road to market is somewhat mapped. Is it possible that fusion will follow the google model and reach the world from someone's garage? It might not seem likely but the chance definitely exists for all those billions invested in traditional designs to be bypassed by one really good innovative idea.
Lockheed - Solve for X: Charles Chase on energy for everyone
Google Talks - Focus Fusion: The Fastest Route to Cheap, Clean Energy
TED - Michel Laberge: How synchronized hammer strikes could generate nuclear fusion
> A Star in a Bottle (ITER - Tokamak)
> National Ignition Facility (NIF - laser based confinement)
> Nuclear man; the humane power station (fission poetry?)
Photo below; General fusion's current experimental prototype on top and what they hope to build below. At the center of the containment vessel, within the spun liquid metal's vortex, plasma rings (think smoke rings) composed of the deuterium-tritium fuel are injected from both above and below which merge to form a single magnetized plasma target. The protruding cylinders you see in the pictures house the pistons used to batter the liquid metal into a fusion susceptible environment. When they are all fired at the same time they send a shockwave through the spinning lead-lithium mixture that gets stronger as it travel towards the center of the vessel where it rapidly collapses the vortex cavity with the plasma in it generating a fusion burst. Quite the turn on wouldn't you say? :)