Overview

Industry has high expectations for superconducting coil applications from those in medicine to others in transport and energy.
Superconducting coils produce heat after moving from a zero to normal resistance zone due to overcurrent and other such characteristics before recovering superconductivity in the neighboring superconducting regions. These characteristics increase temperatures and expand normal zone propagation, which causes a chain reaction (quench). That is why prior analysis to identify the temperature variations during quenching is advantageous.
This case study evaluates a pancake superconducting coil to obtain the temperature and current density variations.

Critical Current Density-Magnetic Flux Density Characteristics of the Superconducting Layer

Fig. 1 illustrates the critical current density versus magnetic flux density characteristics of the superconducting layer

Current / Temperature

Fig. 2 presents the current and the temperature variations at one point on the inner and one point on the outer circumference of the superconducting layer. Fig. 3 illustrates the temperature distribution in the superconducting layer for each current. Fig. 4 indicates the current density distribution (circumferential component) of the superconducting layer for each current. Fig. 5 shows the current density distribution (circumferential component) of the stabilizing layer for each current.
As illustrated by Fig. 2., a current above 70 A produces quenching, which rapidly increases the temperature. The temperature of the inner circumstance reaches -195 deg C about 4.4 seconds before the outer circumference.
As illustrated by Fig. 3, the temperature starts to rise and produces quenching around the lead wire.
As illustrated by Fig. 4 and Fig. 5, the current only flows in the superconducting layer before any quenching. A lower current in the superconducting layer causes current to flow in the stabilizing layer.