Electrical energy production economic assumptions

Magnet coil losses represent the summation of resistive losses in each volume element of the coil. Each volume element dissipates electrical energy at a rate determined by the product of the volume resistivity of the conducting material and the square of current density, i.e., as pj . We will assume that either the current varies sufficiently slowly in time or that the conductors are sufficiently well subdivided that skin effects may be ignored. (This assumption is, however, not without its economic consequences.) The total energy dissipated by the coil is then simply the integral of pj over the volume of the magnet ... 

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