Editing Fusor (section)

===Losses===
It is important to consider the actual startup sequence of a fusor to understand the resulting operation. Normally the system is pumped down to a vacuum and then a small amount of gas is placed inside the vacuum chamber. This gas will spread out to fill the volume. When voltage is applied to the electrodes, the atoms between them will experience a field that will cause them to ionize and begin accelerating inward. As the atoms are randomly distributed to begin, the amount of energy they will gain differs; atoms initially near the anode will gain some large portion of the applied voltage, say 15&nbsp;keV. Those initially near the cathode will gain much less energy, possibly far too low to undergo fusion with their counterparts on the far side of the central reaction area.<ref name=MM>{{cite book |first1= George |last1=Miley |first2=S. Krupakar |last2=Murali |title= Inertial Electrostatic Confinement (IEC) Fusion: Fundamentals and Applications |date= 2013 |publisher=Springer |isbn=9781461493389 |url=https://books.google.com/books?id=f-S5BAAAQBAJ}}</ref>

The fuel atoms inside the inner area during the startup period are not ionized. The accelerated ions scatter with these and lose their energy, while ionizing the formerly cold atom. This process, and the scatterings off other ions, causes the ion energies to become randomly distributed and the fuel rapidly takes on a non-thermal distribution. For this reason, the energy needed in a fusor system is higher than one where the fuel is heated by some other method, as some will be "lost" during startup.<ref name=MM/>

Real electrodes are not infinitely thin, and the potential for scattering off the wires or even capture of the ions within the electrodes is a significant issue that causes high [[Electrical resistivity and conductivity|conduction]] losses. These losses can be at least five orders of magnitude higher than the energy released from the fusion reaction, even when the fusor is in star mode, which minimizes these reactions.<ref>J. Hedditch, "Fusion in a Magnetically Shielded grid interial electrostatic fusion device", Physics of Plasmas, 2015.</ref>

There are numerous other loss mechanisms as well. These include charge exchange between high-energy ions and low-energy neutral particles, which causes the ion to capture the electron, become electrically neutral, and then leave the fusor as it is no longer accelerated back into the chamber. This leaves behind a newly ionized atom of lower energy and thus cools the plasma. Scatterings may also increase the energy of an ion which allows it to move past the anode and escape, in this example anything above 15&nbsp;keV.<ref name=MM/>

Additionally, the scatterings of both the ions, and especially impurities left in the chamber, lead to significant [[Bremsstrahlung]], creating [[X-ray]]s that carries energy out of the fuel.<ref name=MM/> This effect grows with particle energy, meaning the problem becomes more pronounced as the system approaches fusion-relevant operating conditions.<ref name=rider>{{cite tech report |url=https://dspace.mit.edu/handle/1721.1/11412 |title= Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium |first=Todd |last=Rider |publisher=MIT |date=1995}}</ref>

As a result of these loss mechanisms, no fusor has ever come close to [[Fusion energy gain factor|break-even energy]] output and it appears it is unable to ever do so.<ref name=MM/><ref name=rider/>

The common sources of the high voltage are [[Switched-mode power supply#Quasi-resonant zero-current/zero-voltage switch|ZVS]] [[Flyback converter|flyback]] [[High voltage|HV]] sources and [[neon-sign transformer]]s. It can also be called an [[Particle accelerator#Electrostatic particle accelerators|electrostatic particle accelerator]].