Optimum design of superconducting magnet coil for a micro SMES unit

The paper outlines a systematic procedure for the design of a solenoidal co il to obtain maximum stored energy for a given length of normal conductor a nd superconductor. In case of normal conductor, it would suffice if we desi gn the coil to obtain maximum inductance. For superconducting coil, it is e ssential to maximize (1/2Li(2)) as a whole since the value of allowable cur rent depends on flux density which in turn is linked with L. This results i n the design of a coil whose inductance is much lower than the maximum poss ible value and has relatively large diameter as compared to its length and radial thickness Since such a coil requires a cryostat of unusually large n eck, one may choose a sub-optimal design based on commercially available dr um type cryostat for transportable micro SMES units. The paper concludes wi th the dimensions of a solenoidal coil for optimum and sub-optimum designs using superconducting (Nb-Ti) wire of 8 Km length and 1 mm diameter.