Polywell
![A homemade fusor](/Images/godic/202502/03/Homemade_fusion_reactor1137.JPG")
![Farnsworth–Hirsch fusor during operation in so called](/Images/godic/202502/03/Fusor_running1137.jpg")
![Figure 1: Illustration of the 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. The electric field does work on the ions heating them to fusion conditions. (3) The ions miss the inner cage. (4) The ions collide in the center and may fuse.[2][3]](/Images/godic/202502/03/Fusor_Mechanism1137.png")
![Figure 1: Sketch of a MaGrid in a polywell](/Images/godic/202502/03/Polywell_With_Externally_Mounted_Rings1137.png")
The polywell is a type of nuclear fusion reactor that uses an electric field to heat ions to fusion conditions. It is closely related to the magnetic mirror, the fusor, the biconic cusp and the high beta fusion reactor. A set of electromagnets generates a magnetic field that traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. Ions that collide at high enough energies can fuse.