1. The problem statement, all variables and given/known data I need to generate a field of B = 10 T at the center of a magnetic loop (coil). The coil should have r = 70 m. The coil material itself should be a cable of r = 0.2 m. The question, how much mechanical stress is applied throughout the loop? I'm trying to figure out, if such a material (coil) could be made. 2. Relevant equations Not needed, as the magnetic field equations are widely known among the visitors of the forum. On the other hand, I don't know the relevant equations related to the loop stress (tension forces) 3. The attempt at a solution The current flowing through the loop must be 110 GA. Force per meter F/L between wires separated by 1 meter from F/L = mu_0I^2/(2pid): = 2.42×10^15 N (newtons). But I have no idea what to do in the case of a loop (is it lower by factor of 70^2 ? or 140^2?). Is it 1,23*10^11 N or 5*10^11 N? Please help.