Inductive Voltage of Insert HTS Coils Due to Coil Deformation for Ultra-High Magnetic Field Generation

Some rare earth-barium-copper-oxide (REBCO) magnets have been developed as an “insert” to generate ultra-high magnetic fields in a bore of “outsert” background magnets, mainly owing to their good in-field capabilities to generate high fields. Meanwhile, REBCO ultra-high field magnets are known to have some technical challenges such as screening current-induced stress and the consequent plastic deformation that recently attracts much attention from magnet engineers. The coil geometry deformation not only causes mechanical damage to the REBCO layer but affects the screening current distribution itself. Significant coil deformation may lead to deformation of coil current, which results in additional inductive voltage change of individual coils having differential coil inductance. In this article, we have investigated such extra inductive voltage due to coil configuration deformation using electromagnetic numerical simulation together with deformation finite element analysis. The simulation shows that an insert REBCO magnet for ultra-high magnetic field generation may have a small voltage rise induced by the coil inductance change. It also shows the screening current distribution change due to the coil deformation.