Quench development and ultimate normal zone propagation "velocity" in superconductors under fast current change

Normal zone evolution or quench development is a major feature for resistive type fault current limiters design. We studied quench development under fast current rise in several samples of multifilament superconducting wires with a highly resistive matrix. At very fast current rise rates simultaneous quench of the entire sample takes place. It may be described by a characteristic time of a quench. We found that at the highest current rise rate this time is the same for samples with different lengths and cooling conditions made from the same wire. Apparent normal zone "velocity" determined by this time is an ultimate velocity for a given length of a superconducting wire of certain type. We present experimental data about quench development under fast current rise and provide the theoretical estimations of quench parameters.