An oscillator-amplifier KrF discharge laser system capable of providing up to 400 mJ output with 0.1-cm-1linewidth in a 20-ns pulse is described. The output beam divergence is described and shown to be affected by the discharge current. The output beam is near the diffraction limit in the direction parallel to the discharge and about three times the diffraction limit transverse to the discharge. Operation with XeCl at up to 250 mJ with similar linewidth and spatial quality is also described.

An injection-locked unstable resonator rare-gas halide discharge laser of narrow linewidth and high spatial quality

https://aip.scitation.org/doi/pdf/10.1016/j.mre.2016.01.004

From concept to reality - A review to the primary test stand and its preliminary application in high energy density physics

https://aip.scitation.org/doi/pdf/10.1016/j.mre.2016.06.001

Theoretical and numerical research of wire array Z-pinch and dynamic hohlraum at IAPCM

The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a 20 TW pulsed power driver, which can deliver a ∼10 MA, 70 ns rise-time (10%–90%) current to a short-circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. Preliminary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 13 mm to 30 mm, consisting of 132–300 tungsten wires with 5–10 μm in diameter. Multiple diagnostics were fielded to characterize the x-ray radiation from wire-array Z pinches. The x-ray peak power (∼50 TW) and total radiated energy (∼500 kJ) were obtained from a single 20-mm-diam array with 80-ns stagnation time. The highest x-ray peak power up to 80 TW with 2.4 ns FWHM was achieved by using a nested array with 20-mm outer diameter, and the total x-ray energy from the nested array is comparable to that of single array. Implosion velocity estimated from the time-resolved image measurement exceeds 30 cm/μs. The detailed experimental results and other findings are presented and discussed.

Preliminary experimental results of tungsten wire-array Z-pinches on primary test stand

A challenge for the TW-class accelerators driving $Z$-pinch experiments, such as Sandia National Laboratories' $Z$ machine, is to efficiently couple power from multiple storage banks into a single multi-MA transmission line. The physical processes that lead to current loss are identified in new large-scale, multidimensional simulations of the $Z$ machine. Kinetic models follow the range of physics occurring during a pulse, from vacuum pulse propagation to charged-particle emission and magnetically-insulated current flow to electrode plasma expansion. Simulations demonstrate that current is diverted from the load through a combination of standard transport (uninsulated charged-particle flows) and anomalous transport. Standard transport occurs in regions where the electrode current density is a few $1{0}^{4}\ensuremath{-}{10}^{5}\text{ }\text{ }\mathrm{A}/{\mathrm{cm}}^{2}$ and current is diverted from the load via transport without magnetic insulation. In regions with electrode current density $g{10}^{6}\text{ }\text{ }\mathrm{A}/{\mathrm{cm}}^{2}$, electrode surface plasmas develop velocity-shear instabilities and a Hall-field-related transport which scales with electron density and may, therefore, lead to increased current loss.

https://link.aps.org/pdf/10.1103/PhysRevAccelBeams.22.120401

Current transport and loss mechanisms in the Z accelerator

The primary test stand (PTS) is a multiterawatt facility with a current of 8-10 MA and rise time of 90 ns, which is being built for Z-pinch studies at the Institute of Fluid Physics, China Academy of Engineering Physics The PTS consists of 24 modules that are connected in parallel Each module is based on the Marx generator and water pulse forming line as well as laser-triggered spark gap switch working at 5-MV level The nominal total stored energy of the PTS is 72 MJ All the Marx generators and laser-triggered spark gap switches had been tested at full voltage level before the PTS was assembled The design and installation of the PTS are described In this paper, the most recent results of the PTS commissioning will be introduced

Initial Performance of the Primary Test Stand

A high precision laser trigger system is built up in the single test module of Primary Test Stand (PTS) facility. A fourth harmonic, with a wavelength λ of 266 nm, Q-switched Nd:YAG laser was used to trigger the 5 MV multi-gap multi-channel gas switch which was filled with high pressure SF6-N2 mixture gas. The maximum deviation and the standard deviation in the jitter time of the trigger system is ± 0.7 ns and 0.3 ns respectively. The maximum deviation and the standard deviation in the jitter time for the multi-gap multi-channel laser triggering switch is ± 2.4 ns and 1.5 ns respectively. The curve of switch delay-time versus laser energy is obtained, which is helpful for the choice of fitting laser energy. The successful test with two lasers indicated that the design of using twenty-four lasers to trigger twenty-four switches respectively is feasible in ``PTS''.

Primary Investigation into the Laser Triggering Multi-Gap Multi-Channel Gas Switch in a Single Test Module Facility

The laser trigger system for multi-module was built and applied in the single module high power pulse device. The fourth harmonic (λ:266 nm) Q-switched Nd:YAG laser was used to trigger the 5 MV multi-gap multi-channel laser triggering switch. Three lasers were tested together. The experiment results show that maximum deviation (Max-Dev) and standard deviation (StDev) of jitter time of one laser is ±1.5 ns and 0.3 ns. The maximum jitter is lower than ± 2.5 ns between any two lasers.

He An

Papers

Initial Performance of the Primary Test Stand

Primary Investigation into the Laser Triggering Multi-Gap Multi-Channel Gas Switch in a Single Test Module Facility

Laser trigger system for multi-module facility