A5023446842- Laser-Plasma Interactions and Diagnostics
- Pulsed Power Technology Applications
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Electromagnetic Launch and Propulsion Technology
- Plasma Diagnostics and Applications
- Laser-Matter Interactions and Applications
- Electrostatic Discharge in Electronics
- Laser Design and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Combustion and Detonation Processes
- Energetic Materials and Combustion
- Structural Response to Dynamic Loads
- Ionosphere and magnetosphere dynamics
- Electromagnetic Simulation and Numerical Methods
- Ion-surface interactions and analysis
- Gyrotron and Vacuum Electronics Research
- Geophysics and Sensor Technology
- Gamma-ray bursts and supernovae
- Advanced Antenna and Metasurface Technologies
- Astro and Planetary Science
- Semiconductor materials and devices
- Non-Destructive Testing Techniques
- Silicon Carbide Semiconductor Technologies
- Plasma Applications and Diagnostics
University of Michigan
2016-2022
Lawrence Livermore National Laboratory
2022
Sandia National Laboratories
2018-2021
University of Rochester
2019
Airbus (India)
2016
Applied Pulsed Power (United States)
2016
The objectives of this tutorial are as follows: 1) to help students and researchers develop a basic understanding how pulsed-power systems used create high-energy-density (HED) matter; 2) new, compact, efficient technology called linear transformer drivers (LTDs); 3) understand why LTDs an attractive for driving HED physics (HEDP) experiments; 4) contrast with the more traditional Marx-generator/pulse-forming-line approach HEDP 5) briefly review history LTD well some LTD-driven research...
Discrete helical modes have been experimentally observed from implosion to explosion in cylindrical, axially magnetized ultrathin foils (Bz = 0.2 – 2.0 T) using visible self-emission and laser shadowgraphy. The striation angle of the helices, ϕ, was found increase during decrease explosion, despite large azimuthal magnetic field (>40 T). These striations are interpreted as discrete, non-axisymmetric eigenmodes that persist obeying simple relation ϕ m/kR, where m, k, R mode number,...
In this paper, we present experimental results on axially magnetized (Bz = 0.5 – 2.0 T), thin-foil (400 nm-thick) cylindrical liner-plasmas driven with ∼600 kA by the Michigan Accelerator for Inductive Z-Pinch Experiments, which is a linear transformer driver at University of Michigan. We show that: (1) applied axial magnetic field, irrespective its direction (e.g., parallel or anti-parallel to flow current), reduces instability amplitude pure magnetohydrodynamic (MHD) modes [defined as...
Magnetically driven implosions are susceptible to magnetohydrodynamic instabilities, including the magneto-Rayleigh-Taylor instability (MRTI). To reduce MRTI growth in solid-metal liner implosions, use of a dynamic screw pinch (DSP) has been proposed [P. F. Schmit et al., Phys. Rev. Lett. 117, 205001 (2016)PRLTAO0031-900710.1103/PhysRevLett.117.205001]. In DSP configuration, helical return-current structure surrounds liner, resulting magnetic field that drives implosion. Here, we present...
Presented are results from the optical imaging of atmospheric ablations thin aluminum foils. These experiments were performed to evaluate growth temperature perturbations attributed electrothermal instability (ETI). ETI has been shown seed magnetohydrodynamic instabilities on pulsed power-driven initially solid metallic targets, a topic interest various programs in plasma physics that depend stable liner implosions. Experimental observations presented herein demonstrate exponentially growing...
Presented are the results from liner ablation experiments conducted at 550 kA on Michigan Accelerator for Inductive Z-Pinch Experiments. These were performed to evaluate a hypothesis that electrothermal instability (ETI) is responsible seeding of magnetohydrodynamic instabilities and cumulative growth ETI primarily dependent material-specific ratio critical temperature melting temperature. This lower in refractory metals (e.g., tantalum) than non-refractory aluminum or titanium). The...
The Michigan Accelerator for Inductive Z-pinch Experiments (MAIZE) is a single-stage, 1-MA linear transformer driver at the University of Michigan. MAIZE facility has been site various experimental studies, including wire array Z-pinches X-ray source development and cylindrical foil loads implosion stability analysis. In order to better understand investigate these other experiments, 4-frame extreme ultraviolet camera was implemented, optical 12-frame laser shadowgraphy system improved,...
Magnetized Liner Inertial Fusion (MagLIF) at Sandia National Laboratories involves a laser preheating stage where few-ns pulse passes through few-micron-thick plastic window to preheat gaseous fusion fuel contained within the MagLIF target. Interactions with this reduce heating efficiency and mix target materials into fuel. A recently proposed idea called “Laser Gate” removing well before is applied. In article, we present experimental proof-of-principle results for pulsed-power...
This paper expands upon recent experimental results [Campbell et al., Phys. Rev. Lett. 125, 035001 (2020)], where thin-foil liner implosions were driven by a dynamic screw pinch (DSP) and found to have magneto-Rayleigh–Taylor instability (MRTI) amplitudes up three times smaller than in standard z-pinch (SZP). The expanded discussion presented herein includes: (1) detailed comparison of the MRTI growth measured experiment with that calculated from theory; (2) measurements axial magnetic field...
The electrothermal instability (ETI) arises from the temperature dependence of electrical resistivity, $\eta (\mathrm {T})$, in current-carrying materials. When $\delta \eta / \delta \mathrm {T}>0$, as condensed metals, ETI tends to cause exponentially growing perturbations perpendicular direction current. In pulsed power explosions wires, foils, or liners, this causes sections target ablate faster than bulk material, creating an interface perturbation. This perturbation has been shown be...
This paper describes the design of a frequency selective surface (FSS) which provides transmission 228 - 230 GHz radiation and rejection from 164 191.3 with insertion losses under 0.25 dB for TE wave polarization at 45° incidence. state-of-the art filter topology consists two air spaced freestanding perforated screens, comprising unit cell elements resonant slots folded purpose miniaturisation to enhance angular stability. The reported geometry enhances stability (45° ± 10°) FSS beyond what...
Cylindrical foil liners, with thicknesses on the order of 400 nm, are often used in university-scale Z-pinch experiments (∼1 MA 100 ns) to study physics relevant inertial confinement fusion efforts larger-scale facilities (e.g., magnetized liner effort 25-MA Z facility at Sandia National Laboratories). The use ultrathin liners typically requires a central support rod maintain structural integrity target assembly prior implosion. radius this sets limit maximum convergence ratio achievable for...
Wire arrays were widely studied as loads for Z-pinch generators in order to be used multiple scientific applications. More recently, tungsten double planar wire (DPWAs), which consist of two parallel planes wires at a distance few millimeters, suggested and tested indirect drive inertial confinement fusion. Tungsten DPWAs have previously demonstrated the highest (among arrays) radiation yield (up 30 kJ), compact size (few millimeters), strong electron beam production on university-scale...
The quality of warm dense matter samples created by magnetic compression can be largely affected material ablation. When the ablated carries currents, local instabilities grow, which lead to nonuniformities in final pressure. Extending previous work Peterson et al. [Phys. Rev. Lett. 112, 135002 (2014)], Awe 116, 065001 (2016)], and Hutchison E 97, 053208 (2018)], experiments reported here demonstrate that expansion significantly reduced using a simple aerosol spray technique. Coating...
Power-flow studies on the 30-MA, 100-ns Z facility at Sandia National Laboratories have shown that plasmas in facility’s magnetically insulated transmission lines (MITLs) and double post-hole convolute can result a loss of current delivered to load. To study power-flow physics 1-MA, MAIZE University Michigan, planar MITL loads been developed extend into sight for various imaging diagnostics MAIZE. These use 3D-printed dielectric support structures lined with thin foils either aluminum or...
The MAIZE Linear Transformer Driver consists of 40 capacitor-switch-capacitor "bricks" connected in parallel. When these bricks are charged to ±100-kV and then discharged synchronously, the facility generates a 1-MA current pulse with 100-ns rise time into matched load impedance. Discharging each capacitors brick is carried out by breakdown spark-gap switch, process that results emission light. Monitoring this output light fiber optic coupled photomultiplier tube (PMT) an oscilloscope...
In previous studies using the University of Nevada, Reno's (UNR's) high-impedance Zebra Marx generator (1.9 Ω, 1.7 MA, 100 ns), Double Planar Wire Arrays (DPWAs) proved to be excellent radiators, and Foil Liners (DPFLs) useful for future inertial confinement fusion applications. This article presents results joint UNR/UM (University Michigan) experiments with aluminum (Al) DPWAs, Al DPFLs, tungsten (W) DPWAs UM's Michigan Accelerator Inductive Z-Pinch Experiments (MAIZE) generator, a...
Planar wire arrays (PWAs) have been studied on both the University of Michigan’s (UM’s) low-impedance linear transformer driver (LTD), MAIZE ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1 \Omega $ </tex-math></inline-formula> , 0.5–1 MA, and 100–250 ns), Nevada, Reno’s (UNR’s) high-impedance Marx bank generator, Zebra notation="LaTeX">$1.9 1 100 ns). Results with aluminum (low-atomic-number)...
Summary form only given. Experiments are underway to study the stabilizing effects of an axial magnetic field on magneto Rayleigh-Taylor (MRT), sausage, and kink instabilities in imploding liner-plasmas at Michigan Accelerator for Inductive Z-pinch (MAIZE) facility University (UM). The liners were fabricated from ultrathin aluminum foils had thicknesses 400 nm 6.55 mm diameters, imploded by discharging a current 600 kA using 1-MA Linear Transformer Driver1. An independently triggered...
Summary form only given. The electrothermal instability (ETI) arises whenever a current-carrying material has resistivity that depends on temperature. When resistivity, η, increases with increasing temperature, ETI causes striations to perpendicular the direction of current. On pulsed-power-driven, ablating metallic loads, this process can cause sections target ablate earlier than bulk material, creating macroscopic surface perturbation plasma-vacuum interface. Experiments are underway MAIZE...