The Influence of Ex Situ $MgB_2$ Barrier and HIP on the $I_c$ Anisotropy in Double Core $MgB_2//Cu$ Wires

The effect of large $I_{c}$ anisotropy reductions in $MgB_2//Cu$ sheathed wire is presented. The measurements of the critical current in rising magnetic field up to 14 T at 4.2 K were performed. Due to the application of the high isostatic pressure process to the copper sheathed $MgB_2$ wires with the ex situ $MgB_2$ homo barrier around the in situ core the anisotropy for such wires was very small and approached to less than 2% at magnetic field over 4 T. The presented geometry and technology show several advantages in their practical applications.