Design and performance estimation of a 35 T 40 mm no-insulation all-REBCO user magnet

Abstract This paper presents a design of a 35 T 40 mm winding diameter no-insulation standalone magnet that consists of a stack of 52 double pancake (DP) coils wound with multi-width REBCO tapes. The inner and outer diameters and height of the magnet are 40 mm, 221.6 mm, and 628 mm, respectively. It is designed to generate 35 T at an operating current ( I op ) of 179.8 A in a bath of liquid helium at 4.2 K. All the DP coils will be ‘dry’ wound without epoxy, making turns within the DP coils to be essentially ‘self-supporting,’ which is effective to reduce the magnetic stress. To reduce the magnet charging time constant, the so-called ‘metallic cladding’ REBCO tapes will be adopted, where a 1–2 μ m thick stainless steel layer surrounds the tapes hermetically. With an average surface contact resistance ( R ct ) of 170 μ Ω cm −2 , experimentally obtained from a charging test of our recent 3…