Editing Fusor (section)

===Fusor concept===
The fusor is part of a broader class of devices that attempts to give the fuel fusion-relevant energies by directly accelerating the ions toward each other. In the case of the fusor, this is accomplished with electrostatic forces.  For every [[volt]] that an ion of ±1 charge is accelerated across it gains 1 [[electronvolt]] in energy. To reach the required ~10&nbsp;keV, a voltage of 10&nbsp;kV is required, applied to both particles. For comparison, the [[electron gun]] in a typical television [[cathode-ray tube]] is on the order of 3 to 6&nbsp;kV, so the complexity of such a device is fairly limited. For a variety of reasons, energies on the order of 15&nbsp;keV are used. This corresponds to the average kinetic energy at a temperature of approximately 174&nbsp;million&nbsp;Kelvin, a typical [[magnetic confinement fusion]] plasma temperature.

The problem with this [[colliding beam fusion]] approach, in general, is that the ions will most likely never hit each other no matter how precisely aimed. Even the most minor misalignment will cause the particles to [[Scattering|scatter]] and thus fail to fuse. It is simple to demonstrate that the scattering chance is many orders of magnitude higher than the fusion rate, meaning that the vast majority of the energy supplied to the ions will go to waste and those fusion reactions that do occur cannot make up for these losses. To be energy positive, a fusion device must recycle these ions back into the fuel mass so that they have thousands or millions of such chances to fuse, and their energy must be retained as much as possible during this period.

The fusor attempts to meet this requirement through the spherical arrangement of its accelerator grid system. Ions that fail to fuse pass through the center of the device and back into the accelerator on the far side, where they are accelerated back into the center again. There is no energy lost in this action, and in theory, assuming infinitely thin grid wires, the ions can circulate forever with no additional energy needed. Even those that scatter will simply take on a new trajectory, exit the grid at some new point, and accelerate back into the center again, providing the circulation that is required for a fusion event to eventually take place.<ref name=MM/>

[[File:Fusor Mechanism.png|thumb|center|upright=2|Basic mechanism of fusion in fusors. (1) The fusor contains two concentric wire cages: the cathode is inside the anode. (2) Positive ions are attracted to the inner cathode, they fall down the voltage drop and gain energy. (3) The ions miss the inner cage and enter the neutral reaction area. (4) The ions may collide in the center and may fuse.<ref name="Tim Thorson 1996">Tim Thorson, "Ion flow and fusion reactivity characterization of a spherically convergent ion focus", Thesis work, December 1996, The University of Wisconsin–Madison.</ref>]]