Inertial confinement fusion has mostly been the playground of the US. Since the basic idea is that you need a big-ass laserTM that heats and compresses a nuclear fuel, you need to be rich enough to afford the laser system. Not long ago, China joined that club with a laser that was designed to deliver 100 kilojoules per pulse. Although this is still a generation behind the 1.8MJ at the National Ignition Facility in the US, the researchers in China are focusing on innovative ways to achieve high compression.
The key to inertial confinement fusion is that the laser crushes a pellet of nuclear fuel, increasing the pressure and temperature to the point where fusion can occur. This works if you can get a set of laser beams that illuminate the pellet from all sides at once, delivering an even and clean crushing force.
But, what would happen if, instead of applying the force from the outside, the force was applied from the inside and directed outwards?