A5027145290- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Laser-Matter Interactions and Applications
- Solar and Space Plasma Dynamics
- Pulsed Power Technology Applications
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Plasma Diagnostics and Applications
- Astrophysics and Cosmic Phenomena
- Fluid Dynamics and Turbulent Flows
- Astrophysical Phenomena and Observations
- Plasma and Flow Control in Aerodynamics
- Particle accelerators and beam dynamics
- Electromagnetic Launch and Propulsion Technology
- Combustion and Detonation Processes
- Dust and Plasma Wave Phenomena
- Particle Accelerators and Free-Electron Lasers
- Gas Dynamics and Kinetic Theory
- High-pressure geophysics and materials
- Semiconductor Quantum Structures and Devices
- Energetic Materials and Combustion
- Ion-surface interactions and analysis
Imperial College London
2014-2024
Imperial Valley College
1999-2023
St Petersburg University
2017-2023
Academy of Arts
2018-2023
First Light Fusion
2021
National Research University of Electronic Technology
2016-2020
Moscow Power Engineering Institute
2017-2020
Research and Production Complex Technological Centre
2019-2020
Rutherford Appleton Laboratory
2019
Optical Sciences (United States)
2019
A phenomenological model of wire array Z-pinch implosions, based on the analysis experimental data obtained mega-ampere generator for plasma implosion experiments (MAGPIE) [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (1996)], is described. The show that during first ∼80% cores remain stationary in their initial positions, while coronal continuously jetting from to axis. This phase ends by formation gaps cores, which occurs due nonuniformity ablation rate along wires. final starting at...
Resistive magneto-hydrodynamic (MHD) simulations are used to evaluate the influence of three-dimensional inhomogeneities on x-ray power production in wire array Z-pinches. In particular, we concentrate Z-pinch experiments MAGPIE generator at Imperial College. An initial temperature perturbation is stimulate variations core ablation rates that result a highly non-uniform final implosion. Results indicate governed by symmetry implosion surface and rate which current can transfer axis through...
We present the first results of astrophysically relevant experiments where highly supersonic plasma jets are generated via conically convergent flows. The flows created by electrodynamic acceleration in a conical array fine metallic wires (a modification wire Z-pinch). Stagnation flow on axis symmetry forms standing shock effectively collimating axial direction. This scenario is essentially similar to that discussed Cantó and collaborators as purely hydrodynamic mechanism for jet formation...
We present observations for 20-MA wire-array z pinches of an extended wire ablation period 57%+/-3% the stagnation time array and non-thin-shell implosion trajectories. These experiments were performed with 20-mm-diam arrays used double- -pinch inertial confinement fusion [M. E. Cuneo, Phys. Rev. Lett. 88, 215004 (2002)] on Z accelerator [R. B. Spielman, Plasmas 5, 2105 (1998)]. This has smallest wire-wire gaps typically at 20 MA (209 microm ). The this indicates that two-dimensional (r-z)...
We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant astrophysical disks and jets. In these experiments, angular momentum is injected by the ram pressure of ablation flows a wire array Z pinch. contrast previous liquid metal rotation not boundary forces. Axial gradients launch jet upward, which confined combination ram, thermal, magnetic surrounding halo. The has subsonic rotation, with maximum velocity 23±3 km/s....
We present the first results of high energy density laboratory astrophysics experiments which explore evolution collimated outflows and jets driven by a toroidal magnetic field. The are scalable to astrophysical flows in that critical dimensionless numbers such as Mach number, plasma β Reynolds number all astrophysically appropriate ranges. Our use MAGPIE pulsed power machine allow us role pressure creating collimating outflow well showing creation central jet within broader cavity. show...
The evolution of laboratory produced magnetic jets is followed numerically through three-dimensional, nonideal magnetohydrodynamic simulations. experiments are designed to study the interaction a purely toroidal field with an extended plasma background medium. system observed evolve into structure consisting approximately cylindrical cavity embedded magnetically confined jet on its axis. supersonic expansion produces shell swept-up shocked that surrounds and partially confines tower....
The effect of discrete wires on the implosion dynamics wire array Z-pinch experiments at ∼1 MA current level is discussed. data show that formation a core–corona structure leads to gradual radial redistribution mass by precursor plasma flow from stationary cores during first ∼80% time. This phase ends with gaps in cores, which occurs due nonuniformity ablation rate along wires. final starting this time as rapid snowplow-like plasma, previously injected into interior array. density...
A review of recent experiments on the MAGPIE generator (1 MA, 250 ns) aimed at studying implosion dynamics wire array Z-pinches is presented. The first phase dominated by gradual ablation stationary cores and redistribution mass precursor plasma flow. It found that rate depends magnitude global (collective) magnetic field array, increases with field. existence modulation along wires leads to presence a 'trailing' left behind imploding current sheath. trailing provides an alternative path for...
Wire-array z pinches show promise as a high-power, efficient, reproducible, and low-cost x-ray source for high-yield indirect-drive inertial confinement fusion. Recently, rapid progress has been made in our understanding of the implosion dynamics compact (20-mm-diam), high-current (11–19MA), single nested wire arrays. As at lower currents (1–3MA), array (and both outer inner system), variety effects that arise from initially discrete nature wires: long ablation phase 50%-80% current pulse...
A series of experiments has been conducted in order to investigate the azimuthal structures formed by interactions cylindrically converging plasma flows during ablation phase aluminium wire array Z pinch implosions. These were carried out using 1.4 MA, 240 ns MAGPIE generator at Imperial College London. The main diagnostic used this study was a two-colour, end-on, Mach-Zehnder imaging interferometer, sensitive axially integrated electron density plasma. data collected these reveal strongly...
A suite of laser based diagnostics is used to study interactions magnetised, supersonic, radiatively cooled plasma flows produced using the Magpie pulse power generator (1.4 MA, 240 ns rise time). Collective optical Thomson scattering measures time-resolved local flow velocity and temperature across 7–14 spatial positions. The spectrum recorded from multiple directions, allowing more accurate reconstruction vectors. areal electron density measured 2D interferometry; optimisation analysis are...
The remarkable discovery by the Chandra X-ray observatory that Crab nebula's jet periodically changes direction provides a challenge to our understanding of astrophysical dynamics. It has been suggested this phenomenon may be consequence magnetic fields and magnetohydrodynamic instabilities, but experimental demonstration in controlled laboratory environment remained elusive. Here we report experiments use high-power lasers create plasma can directly compared with through well-defined...
We present the first experimental study of plasmoid formation in a magnetic reconnection layer undergoing rapid radiative cooling, regime relevant to extreme astrophysical plasmas. Two exploding aluminum wire arrays, driven by Z machine, generate (SL≈120) which cooling rate far exceeds hydrodynamic transit (τhydro/τcool>100). The generates transient burst >1 keV x-ray emission, consistent with and subsequent layer. Time-gated images show fast-moving (up 50 km s−1) hotspots layer, presence...
Wire array Z-pinch dynamics are studied in experiments with 16-mm diameter arrays of between 8 and 64, 15-μm aluminum wires, imploded 200–260 ns by a 1.4-MA current pulse. Side-on laser probing shows early development noncorrelated m=0-like instabilities an axial wavelength ∼0.5 mm individual wires. End-on interferometry (r-θ plane) azimuthal merging the plasma density 1017 cm−3 90–65 for 8–64 respectively. At same time low-density reaches axis forms precursor pinch 120–140 ns. 0.7–0.85...
The dynamics of wire arrays have been studied using a point-projection X-pinch x-ray backlighter installed in one the return posts MAGPIE generator. Variations diameter (15–50 μm aluminum) and number wires (two or four) enabled backlit images range 140–200 ns after current start. A temporal spatial resolution <1 5 is achieved. radiographic aluminum array show that cores are present at original position until 80% implosion time size 0.25 mm for 0.1 tungsten. very fine structure order...
The implosion of aluminum wire array $z$ pinches driven by a 1.4 MA, 240 ns current pulse is studied. Plasma evolution measured in the $r\ensuremath{-}\ensuremath{\theta}$ plane for first time an end-on laser interferometer. Merging coronal plasmas with density ${10}^{17}{\mathrm{cm}}^{\ensuremath{-}3}$ occurs 90--65 16 mm diam arrays 8--64 wires. Early uncorrelated instabilities (wavelength $\ensuremath{\lambda}\ensuremath{\sim}0.5\mathrm{mm}$) are observed individual wires later...
We present new data from high energy density laboratory experiments designed to explore the interaction of a heavy hypersonic radiative jet with crosswind. The jets are generated MAGPIE pulsed power machine, where converging conical plasma flows produced cylindrically symmetric array inclined wires. Radiative emerge convergence point. crosswind is by ablation plastic foil via soft X-rays region. Our show that deflected action crosswind, angle deflection dependent on proximity foil. Shocks...
Over the last several years, rapid progress has been made evaluating double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough drive high yield ICF capsule. The irradiated sides by z-pinches produce low odd-mode asymmetry. This double-pinch source driven single electrical power...
This paper summarizes the present understanding of processes leading to precursor column formation in cylindrical wire arrays on 1 MA MAGPIE generator at Imperial College London. Direct experimental measurements diameter variation during collapse and phase are presented, along with soft x-ray emission, quantitative radiography. In addition, data from twisted presented which give additional information behavior coronal plasma generated array z pinches. Three stages identifiable data: broad...
Collimated outflows (jets) are ubiquitous in the universe, appearing around sources as diverse protostars and extragalactic supermassive black holes. Jets thought to be magnetically collimated, launched from a magnetized accretion disk surrounding compact gravitating object. We have developed first laboratory experiments address time-dependent, episodic phenomena relevant poorly understood jet acceleration collimation region. The experimental results show periodic ejections of magnetic...
We present a detailed study of magnetic reconnection in quasi-two-dimensional pulsed-power driven laboratory experiment. Oppositely directed fields ($B=3\text{ }\text{ }\mathrm{T}$), advected by supersonic, sub-Alfv\'enic carbon plasma flows (${V}_{\mathrm{in}}=50\text{ }\mathrm{km}/\mathrm{s}$), are brought together and mutually annihilate inside thin current layer ($\ensuremath{\delta}=0.6\text{ }\mathrm{mm}$). Temporally spatially resolved optical diagnostics, including interferometry,...
The Z pinch is enjoying a renaissance as the world’s most powerful yet efficient soft x-ray source which can energize large volume hohlraums for indirectly driven inertial confinement fusion. It has advantages of being and having high energy power density. Its early history will be traced from 18th century to present day. notable feature its instability. various regimes stability analysis reviewed, including resistive finite ion Larmor radius effects. Work in last 10 years on single fibres,...
We present results of high energy density laboratory experiments on the production supersonic radiatively cooled plasma jets with dimensionless parameters (Mach number ∼30, cooling parameter ∼1 and contrast ρj/ρa ∼ 10) similar to those in young stellar objects jets. The are produced using two modifications wire array Z-pinch driven by 1 MA, 250 ns current pulse MAGPIE facility at Imperial College, London. In first set purely hydrodynamic used study deflection cross-wind, including structure...