Pulsed magnets

Abstract

Pulsed magnets are divided into two categories: below 100 T with pulse duration in the range 1 ms-1 s, and above 100 T with pulse duration of order microsecond due to self-destruction of the coil. For both categories, simple scaling laws for the performance are given. For nondestructive magnets, these depend in the first place on the mechanical strength and electrical conductivity of the materials used in coil design; another important parameter is the size of the bore. Together with the energy and power available from the pulsed power supply, this determines peak field and pulse duration. Different types of power supply are discussed, capacitor banks as well as controlled rectification of ac power. For destructive magnets, there is a simple relation between the peak field and the velocity at which the coil structure is expanded by the magnetic force; this can be estimated from shock wave properties of the conductor. The expansion can be neutralized by imploding the coil in a flux compression experiment. High explosives as well as electromagnetic forces have been used for this purpose to obtain fields up to 2800 T. A simple and efficient method is the exploding single-turn coil; this is best suited for experiments up to 300 T.The design and performance of the different magnets is discussed in detail. A few examples for application of these magnets in experiments are given. Prospects for generating higher fields by different methods are discussed, in particular miniaturization on all levels-coils ('micro-magnets') as well as experiments.

Superconducting properties and Fermi-surface topology of the quasi-two-dimensional organic superconductor λ-(BETS)2GaCl4(BETS≡bis(ethylene-dithio)tetraselenafulvalene)

“…The voltage was measured using a high-speed lock-in amplifier. Temperatures as low as ∼ 340 mK were achieved by immersing the sample in liquid 3 He inside a plastic cryostat [17]. Capacitor-driven, ∼ 40 millisecond-duration pulsed magnetic fields of up to 60 T were provided by the National High Magnetic Field Laboratory (NHMFL), Los Alamos.…”

Magneto-electric effect on frequency mixing in atoms

“…The amplitude (12) becomes comparable with (4) for F 0 ≈ αω B 2 R DF /40, that corresponds to F 0 ≈ 1V/cm forB ≈ 100T. Such an exotic field arrangement may be created with the use of pulsed magnetic fields [34].…”

A compact solution for ion beam therapy with laser accelerated protons

“…The maximum magnetic field strength B max achievable by conventional resistive magnets is limited by saturation of the magnetization of the iron-core to a value of B max *1.9 T. However, pulsed magnets are aircore designs powered by pulsed energy supplied by capacitor banks (for more see ref. [53]). By eliminating the core saturation issue, B max achievable with pulsed magnets is mainly limited by the peak current provided by the power supply and by the mechanical strength of the construction materials needed to hold intense magnetic pressures.…”