Magnetically driven implosions on the Z Facility assemble high-energy-density plasmas for radiation effects and ICF experiments. MDIs are hampered by the Magneto-Rayleigh-Taylor (MRT) instability, which can limit achievable stagnation pressures and temperatures. The metallic liners used in Magnetized Liner Inertial Fusion (MagLIF) experiments include astonishingly small (~10 nm RMS) initial...
Underwater electrical explosion of an Al wire can be accompanied by an exothermic process resulting in additional energy transferred to the generated water flow. Here, we report on recent results of a comparison between underwater electrical explosions of single Cu and Al wires. Experiments were carried out using a high-current pulse generator (70 kV, 40 kA, 100 ns). Using fast frame and...
Recently, the concept of the preconditioned wire array Z-pinch was proposed in which the ablation phase was suppressed and the implosion involved all mass of the array. On MAGPIE facility, this was achieved for aluminum wire array by the employing a specially designed two stage wire array, which allowed the generation of a short prepulse current through the wires of the top imploding array,...
We report on initial shock physics experiments performed on the MACH – Mega Ampere Compression and Hydrodynamics – facility at Imperial College London.
The MACH generator is a 2MA, 400ns, 100kV ‘dry air’ Linear Transformer Driver cavity, which can be readily expanded to higher currents and drive voltages. The generator was designed for ease of use, and rapid turnaround with a load region...
Recent results on implosion of strong shock wave (SSW) generated by underwater electrical explosion of a spherical wire array are presented. Microsecond pulse generator (≤38 kV, ≤380 kA, rise time ~1.3 µs) was used for explosion of Cu and Al arrays with radii of 20mm, 25mm and 30mm. A strong light emission from water in the vicinity of the array origin was used to determine the SSW...
The Cygnus Dual Beam Radiographic Facility includes two identical radiographic sources - Cygnus 1 and Cygnus 2. Cygnus is the radiography source used in Subcritical Experiments (SCEs) at the Nevada National Security Site (NNSS). The machine specifications are: Electric - 2.25 MV, 60 kA, 60 ns; Radiation - 4 Rad, 1 mm, 50 ns; Operation - single shot, 2-shots/day. Cygnus has operated at the NNSS...
We investigate the effects of an axial magnetic field ($B_z$) on the current distribution in imploding plasma and the efficiency of the $B_z$-field compression by the imploding plasma. In the experiment, a cylindrical argon gas puff, in which is initially embedded quasi-static magnetic flux (up to 0.4 T), prefills the volume between two electrodes. Subsequently, a pulsed-current (rising to 300...
Development of the technology of using a vacuum arc discharge system for the formation of the metallic gas puff is going in two directions.
The first direction is the use of a plasma jet for the X-ray radiography. We have compared the spatial dimensions of the radiating hot spot based on the use of X-pinch and Point Z-pinch (PZ-pinch is a regular Z-pinch with a small initial size (diameter...
While the Z Facility can routinely deliver 25-27MA current pulses to a variety of high energy density physics experiments, load configurations which require high-inductance (>3.0 nH) hardware typically suffer from reduced current coupling in the form of charged particle losses in magnetically insulated transmission lines (MITLs). These losses: (1) can be difficult to model with conventional...
