Magnetic flux-compression driven by exploding single-turn coils

Abstract

A novel hybrid approach to producing ultrahigh magnetic fields has been successfully demonstrated using a 20 kJ capacitor bank. The explosion of a single-turn copper coil at peak field is used to generate shock-waves, which in turn produce in the aluminum powder filling the single-turn coil a circular insulatormetallic transition advancing towards the coil centre and performing magnetic flux-compression. The flux compression almost precisely doubles the initial flux density generated by the coil, so that some of the Joule energy deposited in the coil is re-use during the process as kinetic energy, rather than being lost as in a standard single-turn experiment. Attempts to scale up the basic arrangement to 80 kJ were only partially successful, but it was nevertheless possible to significantly prolong the duration of the megagauss field that was produced. It is believed that a hybrid method using small explosive charges to produce the shock-waves necessary for flux-compression can certainly be used when attempting to produce record magnetic flux densities in indoor experiments, without the need for a large and costly MJ size capacitor bank.

The magnetic and electric field produced by a proton bunch from the LHC and project of the chamber for investigations in these fields

“…As shown in Fig. 7, at the distance r 0 = 5 mm from the bunch axis the value is equal to 60 T. Those magnetic induction values are comparable to field inductions generated by the coils [1,2]. For comparison, we inform that at the distance r 0 = 50 mm from the bunch axis (the distance equal to the radius of the accelerator tube) magnetic field induction decreases to 6 T.…”

“…The chamber (3) is located directly adjacent to the accelerator tube (2). From the side accelerator tube, the chamber has a well-sealed inside cover (5), which is remotely controlled by a motor (6).…”

“…From the side accelerator tube, the chamber has a well-sealed inside cover (5), which is remotely controlled by a motor (6). The cover can open or close the window (4) in the accelerator tube (2). The chamber contains a rotary head (10), driven by a remote controlled stepper motor.…”

“…Generation of these fields is most often achieved by use of coils supplied with high intensity electric current [1][2][3]. Unfortunately, this method has several deficiencies which limit the upper values of magnetic induction and time duration of these pulses.…”

The magnetic field produced by a protons beam with the three-axial Gauss distribution

“…12 and 13 as well as 14 and 16, the magnetic field induction values B y , B z at the distances 8 µm from the bunch axis had respective values of 11.5 kT and 14.8 kT, and electric field intensity E y , E z achieved suitably 0.58 GV/m and 0.45 GV/m. For comparison, the magnetic field induction pulses produced by explosive compression of magnetic flux reach the magnitudes of 800-1000 T, while record values of induction achieved with this method equaled 2500 T [15,16]. The highest values for magnetic field induction occurring in the focus a very strong laser pulse reach 40 kT, while intensity of concurrent electric field achieved values of 10 14 V/m [17].…”