How would I go about figuring out the voltage output of pic related generator?

The magnet is made (in the manga) by having lighting strike a large ingot of solid iron and then splitting it in two.
>Is it possible to figure out the amount of Magnetic flux those magnets produce
>if we assume their length to be 30cm, width 5cm, and depth 5cm

Is it possible to use the Maxwell-Faraday formula to calculate this generators output since that equation relies on the number of loops, and these are solid discs?
>Let's assume the discs are 2m diameter, and 2mm thick