Method for Controlling Turn-to-Turn Resistance in REBCO Pancake Coils
REBCO pancake magnets with resistive insulation has advantages of self-quench-protection and high current density over its conventionally insulated counterpart. Controlling turn-to-turn contact resistance leads to magnets with long charging/ discharging delays, high energy losses during a field ramp, and high transient electrical currents during a magnet quench. This results in high electromagnetic stresses that could damage the magnet. Very high contact resistance compromises the coil’s self-quench-protection ability risking magnet burn-out during a quench. This is a method of resistance to charge transfer (Rct) control by coating REBCO tape in combination of oxidizing stainless-steel to achieve the targeted Rc, which produces resistively insulated REBCO coils with Rct in a desirable range. It also mitigates the issue of dramatic change in Rct against pressure cycling.