Why is electrical conductivity important in a magnetohydrodynamic generator?

Electrical conductivity is fundamental to a magnetohydrodynamic (MHD) generator because the device's power output is directly proportional to the conductivity of the working fluid. In an MHD generator, electric power is produced by passing an electrically conducting gas or plasma through a magnetic field.12

According to Faraday’s law of induction, this interaction induces an electromotive force that allows current to be collected by electrodes. Because the power density per unit volume depends on the product of the gas conductivity, the square of the gas velocity, and the square of the magnetic field strength, sufficient conductivity—typically 10 to 50 siemens per metre—is required for the system to operate with competitive performance and reasonable physical dimensions. To achieve this, a "seed" of easily ionizable alkali material is often added to the gas.21