Quench current improvement through shape modification of racetrack coil Original Research Article

Superconducting racetrack coils have different shapes from those of ordinary solenoid coils which have the same curvature along the windings. So they have different or worse performance from the viewpoint of quench characteristics due to the different structures. Racetrack coils also have round curvatures along their end portions; however, the main difference of their structures from solenoid coils exists in the straight portions. It is considered that the worse performance is due to the straight portions. In the round portions, there exists strong continuous constraint along the windings against the movement toward the perpendicular direction during coil excitation. On the contrary, in the straight portions, there is almost no constraining. As a result, especially in the case of dry magnet, they show even worse characteristics than solenoid counterparts.