A5019285857- Laser-Plasma Interactions and Diagnostics
- Magnetic confinement fusion research
- Laser-induced spectroscopy and plasma
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Particle accelerators and beam dynamics
- Pulsed Power Technology Applications
- Laser-Matter Interactions and Applications
- Ion-surface interactions and analysis
- High-pressure geophysics and materials
- Atomic and Subatomic Physics Research
- Gyrotron and Vacuum Electronics Research
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Vacuum and Plasma Arcs
- Laser Design and Applications
- Electric Motor Design and Analysis
- Combustion and Detonation Processes
- Electromagnetic Launch and Propulsion Technology
- Nuclear reactor physics and engineering
- Real-time simulation and control systems
- Plasma and Flow Control in Aerodynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Power Transformer Diagnostics and Insulation
University of California, San Diego
2016-2024
General Atomics (United States)
2021-2024
Johns Hopkins University
2021
Cornell University
2021
Sandia National Laboratories
2021
University of Pisa
2012-2017
Magneto-Inertial Fusion Technologies (United States)
2016
National Institute of Optics
2016
Italian Institute of Technology
2016
ETH Zurich
1974
A linear transformer driver (LTD) generator capable of delivering up to 0.9 MA current pulses with 160 ns rise time has been assembled and commissioned at University California San Diego. The machine is an upgrade the LTD-III pulser from Sandia National Laboratories, consisting 40 capacitors 20 spark gap switches, arranged in a 20-brick configuration. was modified addition new trigger system, active premagnetization inductive cores, vacuum chamber multiple diagnostic ports, power feed couple...
Nuclear fusion is a potential source of carbon-free electricity with many concepts in development. The Portable and Adaptable Neutron Diagnostics for Advancing Fusion Energy Science (PANDA-FES) suite has been deployed since 2021 to measure neutron yield, energy, spatiotemporal location at two different Z-pinch devices. This diagnostic can be used variety facilities pursuing the magnetic, inertial, magneto-inertial regimes. These regimes have wide range time scales from less than 100 ns few...
We describe an experiment of atomic spectroscopy devoted to ascertaining whether the orbital angular momentum (OAM) photons has same property interacting with atoms or molecules as occurs for spin (SAM). In our experiment, rubidium vapors are excited by means laser radiation different combinations OAM and SAM, particularly selected inhibit enhance fluorescence according selection rules electric dipole transitions between fundamental state first doublet. Our results clearly show that...
Wire X-pinches (WXPs) have been studied comprehensively as fast (∼1 ns pulse width), small μm) x-ray sources, created by twisting two or more fine wires into an “X” to produce a localized region of extreme magnetic pressure at the cross-point. Recently, alternatives traditional WXP arisen: hybrid X-pinch (HXP), composed conical electrodes bridged thin wire capillary, and laser-cut foil (LCXP), cut from using laser. We present comparison copper wire, hybrid, on single experimental platform:...
Magnetized liner inertial fusion (MagLIF) is an attractive concept for producing thermonuclear reactions. The MagLIF platform involves the operation of Helmholtz coils to apply a 15 Tesla axial magnetic field load region, where cylindrical, fuel-filled metal imploded by <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo>∼</a:mo><a:mn>2</a:mn><a:mn>0</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>MA</a:mi></a:mrow></a:math> current pulse. fringe from...
Gas puff Z-pinches are intense sources of X-rays and neutrons but highly susceptible to the magneto-Rayleigh-Taylor instability (MRTI). MRTI mitigation is critical for optimal reproducible yields, motivating significant attention toward various potential mechanisms. One such approach external application an axial magnetic field, which will be discussed here in context recent experiments on Zebra generator (1 MA, 100 ns) at University Nevada, Reno. In these experiments, annular Kr gas liner...
The Ignitor Program maintains the objective of approaching D–T ignition conditions by incorporating systematical advances made with relevant high field magnet technology and experiments on density well confined plasmas in present machine design. An additional is that charting development line goes from Alcator to ignitor device. rationale for this class experiments, aimed at producing poloidal fields highest possible values (compatible proven safety factors known plasma instabilities) given....
Recent experiments on the 1 MA, 100 ns Zebra driver at Nevada Terawatt Facility University of Nevada, Reno, investigated compression a deuterium target by high-atomic-number (Ar or Kr) gas-puff liner. Pinch stability improved with axial premagnetization 1–2 kG observed as decrease in magneto-Rayleigh-Taylor instability growth. Implosion dynamics and stagnation conditions were studied computationally radiation-MHD code MACH2 using initial that approximate those experiment. Typical average...
The staged Z-pinch (SZP) is a magnetoinertial fusion scheme, where high-Z gas liner implodes onto deuterium target. An accurate measurement of the initial mass distribution, both in and target, crucial to achieve fusion-relevant conditions. This paper presents characterization double-valve injector for SZP experiment, performed on test stand with interferometric visible emission diagnostics. produces an annular profile that peaked at R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
The radial profiles, n(r), Bz(r), and Er(r), for a Flux-Coil ("inductively driven"), Field-Reversed Configuration (FC-FRC) are measured compared to the predictions of Rigid-Rotor Model (RRM), which is an analytic, one-dimensional, time-independent, equilibrium description FRC. Injectors mounted on both ends confinement vessel provide pre-fill plasma. Coaxial coils outside vacuum boundaries annular-confinement accelerate plasma produce density profile by laser interferometry, magnetic-field...
The use of a gas cell as target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, mandatory condition practical applications this emerging technique, especially in multi-stage accelerators. In order full control particle number density region, thus allowing long term LWFA, real-time monitoring is necessary. fact, ideal law cannot be used estimate inside flow based on preset backing pressure room temperature...
A study on the neutron production from single and double gas puff Z-pinches CESZAR linear transformer driver with ∼0.45 MA current 170 ns rise time is presented. Total yield measurements made a LaBr activation detector are compared for three configurations, using nozzle setup. When single, hollow, deuterium shell was used, reliable implosions could only be attained at higher load mass than optimal value to match implosion time, yields of ∼106 per pulse. The use configuration center jet...
The numerical modeling of gas-puff Z pinches involves the nonlinear coupling a broad range complex, multi-physics phenomena that makes such simulations challenging. challenge is further compounded by instabilities can impact dynamics imploding pinches, as magneto Rayleigh–Taylor instability (MRTI). If growth rate and amplitude latter comparable to relevant timescales properties plasma, MRTI dramatically alter implosion dynamics, dictate pinch stability, govern plasma achievable in...
Experiments on a MA-class Dense Plasma Focus (DPF) device have been carried out to investigate changes in neutron production by adding moderate amounts of krypton deuterium fill gas. The yield from Z-pinch devices, including DPFs, conventionally scales as the peak current fourth power. However, dramatic drop-off ∼I4 scaling occurs above 3 MA, which recent modeling [D. T. Offermann et al., Phys. Rev. Lett. 116, 195001 (2016)] attributed transition predominant mechanism beam-target fusion...
Gas puff Z-pinch experiments with annular Ar and Ne gas shells have been conducted on the Compact Experimental System for Ablation Research (CESZAR) linear transformer driver (LTD) 500 kA current 160 ns rise time. Here, we present results from first systematic using a fast (≤200 ns) LTD as driver, in which show that 7% of stored energy capacitors is coupled to plasma kinetic estimated via self-emission laser schlieren images. 0D 1D simulations—which do not allow instability growth thus reach...
The gas-puff $Z$-pinch is a well-known source of x-rays and/or neutrons, but it highly susceptible to the magneto-Rayleigh-Taylor instability (MRTI). Approaches MRTI mitigation include density profile tailoring, in which nozzles are added or modified alter acceleration trajectory, and axial pre-magnetization, perturbations smoothed out via magnetic field line tension. Here, we present two-dimensional magnetohydrodynamic simulations loads driven by an 850 kA, 160 ns driver that suggest these...
1- and 2-D simulations of 1-cm radius, gas-puff liners Ne, Ar, Kr, Xe imploding onto a deuterium target are conducted using the discharge parameters for Zebra (1 MA, 130 ns) driver resistive MHD code MACH2. This is an implementation Staged Z-pinch concept, in which driven to high-energy-density first by shock compression launched diffused azimuthal magnetic field (J×B force), then adiabatic as liner converges on axis. During run-in phase, initial heating preheats plasma, with subsequent...
The gas-puff Z pinch has a long history with myriad applications as an efficient neutron or x-ray source. Its simplicity load configuration makes it suitable for studying fundamental plasma physics phenomena such instabilities and energy transport. For example, the implosion of cylindrical shells onto fusion fuel are inherently susceptible to instability growth on their external surfaces; if unmitigated, then consequences in terms degraded performance can be substantial. Similarly,...
Experiments measuring the azimuthal magnetic field of gas-puff Z-pinch implosions on two drivers significantly different timescales are presented. Using a Zeeman-based spectroscopic technique, measurements <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$B_{\theta }$ </tex-math></inline-formula> compared with calculated values using Ampere's law and load current measured by inductive probes to define...
We present the design of a gas-puff injector for liner-on-target experiments. The is composed an annular high atomic number (e.g., Ar and Kr) gas on-axis plasma gun that delivers ionized deuterium target. supersonic nozzle has been studied using Computational Fluid Dynamics (CFD) simulations to produce highly collimated (M &gt; 5), ∼1 cm radius profile satisfies theoretical requirement best performance on ∼1-MA current generators. CFD allowed us study output density profiles as function...
A semi-analytic model is presented for the gas-puff Staged Z-pinch, a magneto-inertial fusion concept in which an annular liner implodes onto deuterium or deuterium-tritium target. The one-dimensional modification of MagLIF (SAMM) [R. D. McBride and S. A. Slutz, Phys. Plasmas 22, 052708 (2015)], that addresses different set physics inherent to Z-pinch implosion: azimuthal magnetic field transport, shock heating fuel, separate ion electron energy equations, simplified radiation approximates...
Currently there is considerable interest in creating scalable laboratory plasmas to study the mechanisms behind formation and evolution of astrophysical phenomena such as Herbig-Haro objects supernova remnants. Laboratory-scaled experiments can provide a well diagnosed repeatable supplement direct observations these extraterrestrial if they meet similarity criteria demonstrating that same physics govern both systems. Here, we present on role collision cooling rates shock using colliding jets...
The addition of Kr dopant to a deuterium or deuterium–tritium dense plasma focus (DPF) is conventionally thought enhance radiative cooling the imploding sheath, resulting in tighter pinch and, under optimized conditions, increased neutron yield [M. Krishnan, IEEE Trans. Plasma Sci. 40, 3189 (2012)]. In this work, 2D radiation magnetohydrodynamic (MHD) simulations are conducted DPF at peak current levels 2–3 MA range with concentrations 0%, 0.1%, and 1.0% (by volume). Fully kinetic required...
Gas-puff fast Z-pinches are of considerable interest as a neutron source that can be operated in repeatable mode and which may lead to magneto-inertial fusion energy source. In our experiments on the 1-MA pulsed power generator Zebra krypton gas shell was imploded compress central deuterium column. An external axial magnetic field <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$B_{z} = 0.5-3.0 \text {kG}$...