occur during a quench. In addition, the resistive coil will be designed so that it can be shimmed to higher field homogeneity than normal for a resistive magnet. The series-connected hybrid magnet is designed to produce 35 T (40-mm bore) with an inhomogeneity of less than 1 ppm in a 10-mm-diameter spherical volume. Hybrid magnets such as this one are intended to reduce the power consumed to produce the fields they generate rather than maximizing field strength.
One striking characteristic of all of the sciences that use high magnetic fields is how constrained they all are by a single body of technological information—namely, magnet technology. This shared interest notwithstanding, each constituency has historically tended to develop the magnets it needs without much reference to the others. The reasons are several and obvious. The different communities have different missions and need magnets that differ correspondingly. In addition, they are supported by different funding agencies, each with its own perspective.
Recently the HEP and fusion communities have begun to more closely coordinate their development of Nb3Sn wire, an important first step in a healthy direction. Given the intense interest of all magnet user communities in magnet technology and engineering, it would seem to make sense for them to mount a coordinated effort to advance magnet technology. One component of such a coordinated effort might be the construction of high-field instrumentation at NHMFL specifically for the engineering research necessary for the production of high-performance magnets. A second component would certainly be the development of new materials for magnet construction, and a third would be an exploration of other constraints on magnet design and performance. The final ingredient would be a framework to coordinate and integrate communication among the different communities. This framework might start with something as simple as topical conferences and could extend to a management structure for operating a joint program.
It is clear from recent experience that magnets producing fields significantly higher than those available today are going to be either impossible or prohibitively expensive if current technology is used. Rather than supporting an all-out, brute-force effort to prevail using barely adequate technologies, it makes sense to find new approaches that will make it easier (and cheaper) to build the magnets needed. Essential to this enterprise will be the development of both resistive and superconducting materials with improved electrical, magnetic, and mechanical properties. This initiative could be a collaborative enterprise involving both publicly supported researchers and commercial enterprises, but however it is structured, it will certainly require substantial public support.