A 7 T Pulsed Magnetic Field Generator for Magnetized Laser Plasma Experiments

Abstract

A pulsed magnetic field generator was developed to study the effect of a magnetic field on the evolution of a laser-generated plasma. A 40 kV pulsed power system delivered a fast (∼230 ns), 55 kA current pulse into a single-turn coil surrounding the laser target, using a capacitor bank of 200 nF, a laser-triggered switch and a low-impedance strip transmission line. A one-dimensional uniform 7 T pulsed magnetic field was created using a Helmholtz coil pair with a 6 mm diameter. The pulsed magnetic field was controlled to take effect synchronously with a nanosecond heating laser beam, a femtosecond probing laser beam and an optical Intensified Charge Coupled Device (ICCD) detector. The preliminary experiments demonstrate bifurcation and focusing of plasma expansion in a transverse magnetic field.

Ionization injection in a laser wakefield accelerator subject to a transverse magnetic field

“…In addition, we notice that strong magnetic fields on the order of a few tens of Tesla in a small volume can be generated by discharging a high-voltage capacitor through a small wire-wound coil in laboratories [35][36][37], and a pulsed non-destructive magnetic field above 100 Tesla was recently recorded in the Pulsed Field Facility at Los Alamos National Laboratory [38]. Such high magnetic fields are of great interest for controlling laser-plasma interactions [39,40]. Particularly, they could provide an alternative powerful means to control the ionization injection and modify the wakefield structure in the LWFA.…”

Compact pulsed intense magnetic field generator for Shenguang-II upgrade laser facility

“…An electrical trigger system was built using a three-electrode spark-gap gas switch [26] and a high-voltage trigger pulse generator (figure 1(d)). The electric trigger system is more compact and flexible than the laser trigger system used in our past devices [23,24]. The gas switch consists of an anode, a trigger electrode, and a cathode, which is separated by a polycarbonate (PC) insulator.…”

“…Several research groups have developed pulsed strong magnetic field devices [13]- [22] that work in conjunction with laser facilities. In the University of Science and Technology of China, we developed two pulsed magnetic field generators [23,24], working in a high vacuum and low vacuum environment, respectively, to perform experiments of magnetized laser fusion, the interactions between solar wind and magnetosphere, and magnetic collimated astrophysical jets, etc. on a smallscale laser facility.…”

“…Firstly, the target chamber with 1.3 m radius means that the pulsed magnetic field device cannot be placed inside the target chamber and adjusted by the ten-inch manipulator (TIM) as that on OMEGA laser facility with larger target chamber [19]. The coils also cannot be finely adjusted by manipulating the entire magnetic field device placed outside the target chamber as our past devices on smaller target chamber [23,24] due to the long transmission line (equals to target chamber's radius). Secondly, the target chamber of SG-II upgrade laser facility will deform after vacuuming, which indicates that the coils component must be detached from rigid connection with the other part of the discharge device fixed on the target chamber to keep the coils' position.…”

Summary of laser plasma physics sessions at the first AAPPS-DPP conference

“…Hu [L-I29] reported their work on laser's interaction with magnetized plasma. A magnetized laser plasma facility was built at University of Science and Technology of China (USTC), which is composed of a nanosecond heating laser beam (6 J/527 nm/7 ns), a femtosecond detecting laser beam (2 mJ/800 nm/50 fs), and a 7-30 T pulsed magnetic field generator (Hu et al 2015). A series of laser plasma evolution experiments were performed (Tang et al 2018).…”