A QUASI-FORCE-FREE SUPERCONDUCTING TOROIDAL MAGNET ACHIEVING "SHORT-SAMPLE" PERFORMANCE

The force-free magnets are those in which the current density J is everywhere parallel to the field H, i.e. J=αH, where a is a scale function called force-free factor or function.Therefore the Lorentz force f is equal to zero, since f=μJ×H=0.However, from the virial theorem of mechanics it can be verified