MHD power generation???

Question

In magnetohydrodynamic (MHD) power generation, we use liquid metals and gaseous conductors. If the conditions are taken below critical, is it not a good option to use superconductors for that purpose? And what is the scope for semiconductor usage (with proper doping)?

Answer 1

The generator current density is J=\sigma V X B, where \sigma is conductivity, so at first it would seem a superconductor would supply infinite current. However, this equation also depends on B, so B field penetration into the flowing conductor is needed. It must, therefore, be resistive. Superconductors fully exclude any applied B by the Meisner effect; it's a perfect diamagnetic material

Edit: Oh yes, J is reduced by \sigma E, but the point is still valid.