Development of multifilamentary Nb3Sn conductors for fusion research

A program at Lawrence Livermore Laboratory to develop multifilamentary Nb
3
Sn conductors suitable for use in constructing fusion research magnets has resulted in the commercial production of conductors having cross-sectional areas in the range 0.06 cm
²
to 0.84 cm
²
. Critical current densities near the goal of 10
⁴
A/cm
²
at 12 T and 4.2 K have been obtained in conductors produced by two different techniques. The latest results of this program are presented and discussed.