 Tests included measuring an internal beam of electrons, comparing the machine with and without a magnetic field, measuring the voltage at different locations and comparing voltage changes to the magnetic and electric field strength.A 2015 paper entitled "Fusion in a magnetically-shielded-grid inertial electrostatic confinement device" presented a theory for a gridded inertial electrostatic confinement (IEC) fusion system that shows a net energy gain is possible if the grid is magnetically shielded from ion impact.The analysis indicates that better than break-even performance is possible even in a deuterium-deuterium system at bench-top scales.