Patent ID: 8174803

Claim:
A system for creating a magnetic field including: a first branch comprising a superconducting magnet configured to produce said magnetic field, said magnet being formed by a coil inductance (L′) in series with a residual resistance (R′ 2 ); a second branch comprising a protection resistance (R′ 3 ); a third branch comprising a power supply; a fourth branch formed by a resistance (R′ 1 ) mounted in series with a current-limiting superconducting device switching from a low-resistance state to a high-resistance state when the current passing therethrough exceeds a breaking current, said superconducting device having an inductance at least 10 5 times less than that of the coil (L′), and said first, second, third and fourth branches being mounted in parallel, said system presenting at least three modes of operation: a first mode of operation, corresponding to a charge mode or discharge mode of the magnet, in which: said power source is connected to said magnet so as to increase or reduce the current in the magnet, said current limiter being in its high-resistance state; a second mode of operation, corresponding to a normal mode of operation, in which: said power source is connected to said magnet, said limiter being in its low-resistance state; a third mode of operation, corresponding to the rapid discharge mode of the magnet in said protection resistance (R′ 3 ), in which: said power source is disconnected from said magnet, said limiter being in its high-resistance state; wherein activation of the state of said limiter in said three operation modes is done in a passive manner without resorting to an external command.