I’ve added a link in the sidebar to the Open Source Fusor Research Consortium. For those not familiar with a fusor, it is a simplistic device that uses electrostatic forces to fuse deuterium.
These devices are presently not capable of achieving scientific break-even (more power from fusion than required to initiate the reaction) but there are people who hope to change that. Building this device is within the reach of an amateur experimenter and many people have done so. This website covers work on this specific device as well as related devices.
The device consists of two concentric spherical grids within a vacuum chamber in which air is pumped out and a low pressure deuterium gas is present. The inner most grid is charged with a negative charge, the outer grid with a positive charge, around 40 Kv between them. This strips electrons from the deuterium atoms and then accelerates the nucleus towards the center of the sphere where they collide with sufficient energy that some of them fuse.
What limits the efficiency and power output of these devices are the grids. A significant portion of the accelerated ions collide with the grid rather than continuing on to the center of the sphere. This heats the grid and results in a current flow which consumes and wastes power.
A particularly promising approach invented by Dr. Robert Bussard has produced fusion levels 100,000 times that of the original Farnsworth Fusor’s best run. It achieves this by eliminating the physical grid and using magnetic fields to steer electrons to create virtual grids.
Electrons are much lighter than deuterium nuclei but have the same magnitude charge (but opposite polarity). This allows a much weaker magnetic field to steer electrons into a desired configuration than is required to confine a plasma in thermal approaches to fusion.
Dr. Bussard’s research was funded by the US Navy for a number of years, but funding had run out in 2005. By that time the scaling laws of these devices had been determined and Dr. Bussard is confident that a device can be made that produces power.
Dr. Bussard, at 78 and with health issues, may never have the opportunity to bring his device to it’s potential. That is a shame because unlike thermal fusion, this device has the potential for fusing aneutronic fuels such as boron with hydrogen producing power without radiation. And such a device may be made small enough to power trains, ships, or large airplanes.
Take a look at the site, it’s a good site to follow if you want to know what is happening in the world of small scale amateur fusion devices.