Parameters and requirements of superconducting focusing quadrupoles for heavy ion fusion

In a heavy ion fusion driver, arrays of superconducting quadrupoles will transport parallel beams through a sequence of induction acceleration cells. The development of such arrays is a unique and challenging task. Since magnetic transport is one of the most expensive subsystems, economy of fabrication is a primary consideration. A compact design is essential to limit the size and cost of induction cores. Special edge coils have to be implemented to adjust the field in outer cells and terminate the magnetic flux. The development of superconducting magnets for both near term experiments and the ultimate driver application is actively pursued by the U.S. Heavy Ion Fusion Program. The main parameters and requirements are discussed, and the R&D status and plans are presented.