Conveners
Poster - Charged Particle Beams and Accelerators and High Energy Density Plasmas and Applications
- Alexander Velikovich (Plasma Physics Division, Naval Research Laboratory)
Governments and corporations around the world have billions of dollars of assets in Low Earth Orbit (LEO). It is, therefore, valuable to analyze the environment, including the thermal ions, in LEO. These thermal ions are critically important to establishing the “ground” potential for all elements of the spacecraft electrical system. Before instruments are launched to make such measurements,...
X-ray and particle beam source designs at the Saturn accelerator would greatly benefit from a better understanding of the power flow in the center vacuum section. The Chicago particle-in-cell (PIC) code has been used to create a model of the insulator stack-MITL-diode system to attempt to match simulations to experimental B-dot current data. The stack voltage waveforms for the different MITL...
The pulsed low-energy (up to 15 keV) forevacuum plasma-cathode electron sources, operating at pressures 3-30 Pa, provide direct processing of dielectric materials (ceramics and polymers) due to compensation of negative charge on the dielectric surface by beam-produced plasma and by non-self-maintained discharge between charged surface of the dielectric and a grounded vacuum chamber. In...
A plasma source of a ribbon electron beam for electron beam generating with a cross section of 10*250 mm in the fore-vacuum region of pressure was created. The cathode was a rectangular cavity with an extended slit. To increase the uniformity of the electron beam current distribution, a multi-aperture extraction system was used. A part of the anode, facing the extractor, contained 60 holes...
The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device located at Oak Ridge National Laboratory which serves as a test-stand to develop the plasma source concept for the Materials Plasma Exposure eXperiment (MPEX). Recent experiments have demonstrated the heating of electrons via Electron Bernstein Waves (EBW) in this linear configuration using 28 GHz...
SPIDER is the full-size prototype of ITER Neutral Beam Injector ion source, in operation since June 2018 as a project of the ITER Neutral Beam Test Facility located at Padova, Italy. It consists of an inductively coupled plasma source and an extraction system to accelerate the produced negative ions up to 100 keV energy. The plasma source is composed of 8 drivers, operated in low hydrogen gas...
Pseudospark discharge has attracted significant attention for the generation of high density, energetic and high brightness electron beams with fast current rise for the growing applications on extreme ultraviolet and X-ray radiation source, microwave and THz radiation generation, surface modification, etc. [1-2]. In this work, the investigation has been carried out for the generation and...
Cold atmospheric pressure (CAP) plasma has been shown to kill bacteria and destroy biofilms through reactive etch and sputter activity and could be used on industrial surfaces in the food processing industry where microbial contaminants are a source of food-borne illness. Our group has developed a parallel plate plasma source using embedded electrodes. Results have demonstrated that our...
Atmospheric-pressure plasma sources have been intensively studied because of their various industrial applications. Especially atmospheric pressure plasma has a strong potential for biomedical and surface treatment applications. In this paper, we report properties of the energy-controlled atmospheric pressure plasma. The independent control of the voltage and the discharge current is suggested...
Eagle Harbor Technologies (EHT), Inc. is developing radio-frequency (RF) solid-state switching power supplies without the need for a 50-ohm matching network. The ability to remove the 50-ohm matching network from RF plasma generation systems significantly simplifies the design while allowing for a faster response time to changing plasma conditions. This system takes advantage of EHT’s...
A portable X-ray generator for plant root imaging is being developed. The generator mainly includes a Cockcroft-Walton DC high voltage generator, which provides a high voltage DC bias to an x-ray diode, and a metallic target to convert the electron beam into X-rays. A backscatter imaging technique is used, where X-rays are projected onto the plant target (the roots buried in soil), and Compton...
The study of electron beam generation in a dense plasma focus (DPF) can yield insight into the physical mechanisms that lead to the formation of electron beams in pinched plasmas. A detailed understanding of these mechanisms may enable the production of a high-intensity x-ray source for various applications. Plasma polarization spectroscopy (PPS) is a novel diagnostic tool that will be...
Several experiments have shown that the anode initiates breakdown of vacuum gaps in cases where the anode and cathode field enhancements are approximately equal.1 The previous understanding was that only explosive emission at the cathode initiates breakdown between metal electrodes in vacuum with nanosecond pulses. Past experiments have shown clear evidence of particles from the anode...
Effects of the electron beam parameters on hydrodynamic response of aluminum: measurements and simulations.
J. Gardelle, B. Bicrel, B. Cassany, A. Galtié, D. Hébert and N. Szalek.
CEA/CESTA, 15 avenue des Sablières, CS 60001, 33116, Le Barp, France
The study of the dynamical response of material under shocks produced by electrons requires a good knowledge of these when they interact with...
PROPAGATION OF ELECTRON BEAMS IN GAS CELLS
B. Cassany, D. Hebert, J. Gardelle, P. Modin, N. Szalek,
CEA/CESTA, CS 60001, 33116 Le Barp, France
K. Bell, C. H. Moore, B. Medina, M. Bettencourt
Sandia National Laboratories
Albuquerque, NM 87185 USA
In this work, we present the first results of joint Sandia National Laboratories (SNL) and CESTA experiments where electron beams are produced...
In the framework of X-Ray Flash Radiography, we investigate the propagation of an intense (2 kA), pulsed (60 ns) relativistic (4 MeV) electron beam (REB) through a cold plasma. The REB electrons interact with the plasma through binary collisions and collective response, whose importance depends on the ratio of plasma over beam density. Under some conditions, the collective response induces...
Photoemission is one of the fundamental processes to produce electron beams and is important to particle accelerators, electron microscopy, and vacuum electronics [1]. Recently, an analytical model for photoelectron emission from metal surface illuminated by a laser field was developed, by solving the time-dependent Schrödinger equation exactly [2, 3]. The model includes the effects of dc...
The Saturn accelerator was commissioned in 1987 as a 5.4 MJ, 2.7 MV flash x-ray machine that delivers 750 kJ at 2.1 MV to a three-ring Bremsstrahlung (BREMS) diode with a peak power of 25 TW and FWHM pulse width of 40 ns. In December of 2017 and June of 2018 experiments were conducted using varying numbers of Saturn pulsed power modules connected to one of the three Saturn parallel BREMS...
As part of a continued validation effort for Sandia’s new plasma code, EMPIRE, we have modeled and are simulating the RKA beam experiment. Specifically, we have improved previous simulations of the RKA diode by using input parameters that more closely match the experiment and implementing Space Charge Limited (SCL) emission from the cathode velvet into EMPIRE. Moreover, we have begun...
Ion energy distribution function (IEDF) plays a significant role in numerous plasma enhanced manufacturing processes in the semiconductor industry. To measure the IEDF, retarding field energy analyzers (RFEA) have been widely used. To extend the capability of measuring higher ion energies and minimize impact on manufacturing processes, a traditional RFEA was redesigned and embedded in the...
Improvement of Heaven-I high power excimer laser facility for ICF study
Zhixing Gao, Jing .Li, Zhao Wang, Fengming Hu, Baoxian Tian, Ze Lu
China Institute of Atomic Energy, Beijing 102413, China
The recent works on Heaven-I KrF laser facility was introduced to improve the performance of E-beam pumped laser for ICF study. The technique of EFISI had been used to improve the...
Auto-collimation and monitoring of KrF laser beam in the E-beam pumped high power excimer laser facility
Jing li, Fengming Hu, Zhixing Gao, Zhao wang, Baoxian,Tian
(China Institute of Atomic Energy, Beijing, 102413)
Abstract:
The characters of the laser beam, such as the aiming precision and irradiation intensity on target, are important for the laser-matter interaction study. To ensure the...
Portable and cheap neutron sources are in demand for various applications such as cancer therapy, fusion material study, explosive materials etc. Among various neutron sources, inertial electrostatic confinement fusion (IECF) is an extremely simple device that produces neutron yield typically ~ $10^{8}$ DD n/s. IECF is basically a fusion concept where the lighter fuel ions (deuterium, tritium)...
Electron cyclotron heating (ECH) is used as one of the most important auxiliary heating method for plasma heating in modern fusion research. In addition to plasma heating, EC system is used for plasma current drive and control of plasma instabilities such as NTM (Neoclassical Tearing Modes). ECH (Electron Cyclotron Heating) system for KSTAR (Korea Superconducting Tokamak Advanced Research) is...
The U.S. Naval Research Laboratory has converted the repetitively pulsed Electra krypton fluoride (KrF) laser system to an electron-beam (e-beam) pumped argon fluoride (ArF) laser. Operating at 193 nm, ArF has the potential of being the most efficient excimer laser and is a good candidate for an inertial confinement fusion (ICF) driver. The shorter ultraviolet wavelength increases energy...
The Dense Plasma Focus (DPF) is a compact coaxial pulsed plasma source of radiation, especially neutrons. Researchers have known for some time that a DPF will produce more neutrons than one would expect from a purely thermal fluid prediction [S. Lee and S. H. Saw, Appl. Phys. Lett. 92, 021503 (2008)], and therefore the most accurate DPF simulations take into account kinetic effects [A....
The Spheromak Turbulence Physics Experiment (STPX), a new large diameter (1.5 m) gun injected spheromak confinement system, has been constructed recently at FAMU for use originally in studying equilibrium, reconnection, turbulence, dust transport, and astrophysical phenomena, and for diagnostic probe development. We present details on its design, construction, operation, performance...
The Pulsed Fission-Fusion Engine (PuFF) propulsion concept combines utilizes targets of fission and fusion fuel layers compressed and heated by a pulsed z-pinch driver. Fusion may provide the neutron seed to ignite the fission fuel, which in turn provides fission fragment heating to sustain the fusion reactions. The propulsion system utilizes a z-pinch to compress PUFF targets. Thermal...
To achieve the goal of fusion TAE Technologies developed the C-2W experiment, an advanced beam-driven field-reversed configuration (FRC), which is the world’s largest compact toroid device. It is a linear system which consists of two theta-pinch formed FRCs, translated and merged in a confinement vessel. Each of C-2W’s Formation sections consists of two sets of magnets. First, a rotating...
Extreme ultraviolet (EUV)/soft X-ray radiations are highly important in the growing areas of surface modification of polymers for biocompatibility improvements, radiography of small objects for potential biological applications, etc. [1-2]. In this work, theoretical and plasma simulation studies have been presented for the generation of EUV/soft X-ray radiations from the pseudospark discharge...
Experimental observation of aluminum (Al) combustion realized in microsecond timescale under-damped underwater electrical explosion of Al wire is presented. Experiments were carried out using pulse power generator with peak current ~220 kA and rise time of ~1.6 µs. Using time-resolved spectroscopy, absorption bands of AlO oxide was obtained in the case of Al wire explosion with diameter <0.6...
We have demonstrated a thin liquid-metal load for repeatable applications using pulsed-power discharge. To understand the liquid-metal behavior, we measured the liquid-metal diameter as a function of hydrodynamical normalized number. We found that the length and diameter of liquid-metal can use the hybrid X-pinch system. To demonstrate the thin liquid-metal load, we used a pulsed-power system...
Target machining using datum point tooling for
Precision High Energy-Density Liner Implosion Experiment (PHELIX) magnetic implosion system
Franklin Fierro, Patrick M. Donovan, John C. Lamar, Jeff Griego, Randall B. Randolph, Christopher L. Rousculp
Los Alamos National Laboratory
Los Alamos NM, 87545
Cylindrical driven shock experiments examining damaged surface hydrodynamics and...
We are planning detailed spectroscopic studies of the X-ray bursts produced by hybrid X-pinches using ~20 ps time resolution X-ray streak cameras. The purpose is to investigate whether radiative collapse occurs in the micropinches that produce the X-ray bursts. In order to do that, we want 1 strong X-ray burst from the hybrid X-pinch at a time that is reproducible within ± 1 ns. As a first...
The electrothermal instability (ETI) is a Joule heating-driven instability that can initiate in the solid state in solid liner-driven fusion. In the solid state, the ETI generates azimuthally correlated (striated) temperature and density perturbations. These striations may seed the magneto Rayleigh-Taylor (MRT) instability, which has been shown to limit stagnation pressure and fusion yield....
Physical properties of a guiding cone for fast ignition in an inertial confinement fusion system are one of the key issues to understand the behavior of laser-generated fast electrons. The guiding cone will be changed from a solid state to a region of warm dense matter (WDM) irradiated by an intense-laser. The conversion efficiency, which is defined by the ratio of the energy of fast electrons...
Laser shock peening (LSP) is a widely known technique, which is used in industry to improve the properties and performance of metallic components. Laser induced compressive residual stresses (RS) allow to enhance the fatigue life of aircraft structures [1]. Due to deeper depth and higher magnitude of RS in the target material, this technique is a potential substitute of the conventional...
Till recently, measurements of the magnetic field in gas-puff z-pinch implosions were limited to low density and temperatures typically found at very early times and outside the pinch radius ( $r\ge9$ mm and $t\le-90$ ns). However, recent, more accurate measurements at higher densities and temperatures at various R and Z-locations on the generator at the Weizmann Institute of Science (WIS)...
Fast linear transformer drivers (FLTDs) are a rapidly developing field of pulsed-power technology in recent years, which is used to output high-power, high-current pulses. However, an FLTD on terawatt level usually contains more than thousands of switches. As a result, the fault of self-discharge of switches is common in FLTDs. This brings a. important problem that when self-discharge occurs,...
Experiments of two-wire Z-pinches are carried out, in which an adjustable current prepulse is introduced to preheat the wires before the main current start. Experimental results show that the time delay (Tdelay) between the prepulse and the main pulse has a fatal effect on the ablation behavior and the dynamic of implosion.
The two-wire load is heated to a core-corona state by the prepulse...
The electrothermal instability (ETI) is driven by Joule heating and arises from the dependence of resistivity on temperature. When a metal is Joule heated through the boiling point, ETI may drive azimuthally correlated surface density variations or “strata” which provide the dominant seed for subsequent growth of the magneto Rayleigh-Taylor (MRT) instability. Simulations of z-pinch...
Recent results from experiments of magnetically-driven pulsed power solid
liners have exhibited electrothermal instability (ETI) growth early during
the phase transitions of the conductor. Understanding the development of
these instabilities and potential stabilization mechanisms could play a sig-
nificant role in the success of fusion concepts such as MagLIF (Magnetized
Liner Inertial...
Millimeter-wave radiometer and coherent Thomson scattering diagnostics are being developed in order to characterize radiated power and turbulent density fluctuations in pinch plasmas in the COBRA accelerator at Cornell University. The purpose of these measurements will be to study the overall power balance in COBRA plasmas under various conditions. An initial radiometer channel will operate in...
The magnetic field diffusion into a conductor driven by intense pulsed power is of interest for current-driven instabilities such as the electrothermal instability (ETI). ETI is thought to develop on the surface of a conductor due to uneven ohmic heating and variation in resistivity that follows the spatial distribution of the current density as impacted by surface roughness and inclusions....
Z-pinch is known to be unstable due to MHD kink ($m=1$) and sausage ($m=0$) modes [1]. Recent experiments demonstrated that these modes can be stabilized by a radially sheared axial flow [2]. Typical MHD models are usually unable to adequately describe evolution of short wave length modes as they ignore finite ion gyroradius $\rho_i$ effects. Gyrokinetic simulations of the $m=0$ mode performed...
The PBEX (Plasma Bubble Expansion eXperiment), being conducted on the University of New Mexico’s HelCat (Helicon-Cathode) basic plasma science device, utilizes a coaxial plasma gun to launch plasma jets and bubbles (spheromaks) into lower density magnetized plasmas. The goal of these experiments is to study the dynamics of magnetic relaxation processes in the presence of background plasma. ...
The Zeeman splitting of visible spectral lines is measured to infer the magnetic field and current profiles in gas puff z-pinches. In high current (>1MA) z-pinches, the plasmas are highly ionized and most of the emitted photos are in XUV or x-ray region. It is difficult to apply the Zeeman splitting spectroscopy there because there are not many detectable visible lines. We have identified...
Emission spectra from a microsecond x-pinch were studied in the soft x-ray region which give information about the radiating hot spot plasma. The spectra were collected using a flat crystal spectrometer from aluminum and molybdenum in a 2x25 µm wire x-pinch configuration. We present results that show aluminum reaching the hydrogen-like state and molybdenum reaching the neon-like charge state,...
The 650 kA Hawk pulsed power generator at NRL has been configured as a fast (1.2 μs), high inductance (607 nH) driver for a dynamic dense plasma focus load. The current pulse is initiated in a deuterium plasma that is injected radially by three Marshall guns. This plasma is accelerated through a coaxial region, and pinches onto neutral deuterium injected axially by a gas-puff valve. Promising...
The Z-machine housed at Sandia National Laboratories is instrumental in plasma physics research across a range of applications. University-scale z-pinch experiments, such as gas-puff z-pinches, can inform the high-value experiments conducted at Sandia. A gas puff z-pinch requires gas to be puffed into the region between two electrodes, which is then pulsed with a high voltage [1]. The gas is...
Diagnostics of pulse-power systems is a challenging experimental task. The high electric and magnetic fields that are usually involved in their operation can interfere the measurement, and moreover, can damage sensitive electronic data acquisition systems. Optical fibers, being almost immune to electric noise pick-up, are thus favorable as gauges or transmission lines in noisy systems.
In...
In order to study the mechanisms of deuteron acceleration and neutron production, deuterium gas-puff z-pinch experiments are performed at the terawatt-class GIT-12 generator. In these experiments, during the stagnation of z-pinch implosion at a time of about 700 ns, the generator current achieves approximately 3 MA. After a relatively stable implosion, the disruption of the z-pinch by...
A super-intense laser pulse, incident on a thin foil target, can create plasma structures with accelerating fields on the order of TV/m, accelerating ions to multi-MeV energies. The 10$^{20}$ W/cm$^{2}$, linearly polarized Texas Petawatt Laser (TPW) facility was employed to accelerate high energy titanium ions from ultrathin (60 to 200 nm) planar titanium foil targets. A clear optimum target...
We are developing the Topanga code for predicting E3 electromagnetic pulse building on our experience with hybrid plasma simulation. The E3 component has a long pulse, lasting tens to hundreds of seconds. It is caused by the nuclear detonation's temporary distortion of the Earth's magnetic field. The E3 component has similarities to a geomagnetic storm caused by a solar flare. Like a...
The use of stark broadening in plasma diagnostics is a common tool to derive information about electron density and temperature distributions. In contrast, only limited theoretical work is available, which can be used to interpret experimentally acquired spectra. Current ab initio models do not give a sufficient explanation on the driving effect of radiation interaction with the plasma...
This paper describes three sets of experiments regarding the generation and propagation of nitrogen emission at 337.1 nm. 8 stage PFN (Pules forming network) Marx generator was used in the first set of experiments. The generator of 50 Ω internal impedance produces a “square” shaped voltage waveform across 50 Ω resistor. When the generator is applied to the experimental setup, the glow-like...
