Analysis of Fast Neutral Particles in Inertial Electrostatic Confinement Fusion Devices
Analysis of Fast Neutral Particles in Inertial Electrostatic Confinement Fusion Devices

Author:

Publisher:

Published: 2014

Total Pages: 285

ISBN-13:

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A neutral particle analyzer was engineered specifically for inertial electrostatic confinement (IEC) fusion devices for the first time and particularly for studies with relevance to operation with helium-3, an advanced fusion fuel. For experiments with helium, this technique yields energy distributions of escaping fast neutral particles produced by atomic and molecular processes between energetic ions and background gas, as well as the line-of-sight-averaged energy distributions of fast ions. The setup uses a 10 nm carbon foil as a stripping target for incident fast neutral particles and cylindrical electrodes with a variable relative voltage for deflecting ions of a specific energy per unit charge into a continuous electron multiplier. The new diagnostic can be used to study neutral particles with kinetic energies between 5 and 170 keV, with a measured energy resolution of 2-4% between 5 and 30 keV. Initial neutral particle analysis experiments have been performed at cathode voltages up to 60 kV for IEC devices in the glow discharge, external-ion-source and filament-assisted source plasma configurations, with both helium-4 and deuterium gas. Comparisons between experimentally determined neutral-particle energy distributions and predictions by the VICTER and HeVICTER integral-transport numerical codes on spherically convergent ion flow in IEC devices show that the codes do not capture many details of the relevant physics. For helium-4 experiments in the external-ion-source mode, the energy distributions were confirmed to be significantly harder at 0.2 millitorr than at 5 millitorr, which is essential for the prospects of the configuration for increasing helium-3 fusion rates.

Fusion Neutron Production Using Deuterium Fuel in an Inertial Electrostatic Confinement Device at 10 to 200 Kilovolts
Fusion Neutron Production Using Deuterium Fuel in an Inertial Electrostatic Confinement Device at 10 to 200 Kilovolts

Author: Aaron N. Fancher

Publisher:

Published: 2018

Total Pages: 0

ISBN-13:

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This work details the advancement and understanding of fusion neutron generation capabilities using a deuterium fueled spherical gridded inertial electrostatic confinement (IEC) device operating up to 200 kV at the University of Wisconsin-Madison. The goal of this work was to extend the experimental and theoretical understanding of gridded IEC operations to previously unachieved 200 kV cathode operation and to investigate long term trends in the neutron production rate performance. To support this experimental investigation, hardware with the capability to reliably sustain 200 kV operation was successfully developed by constructing a resistively divided 2-stage high voltage vacuum feedthrough. Repeated measurements of the neutron production rate under fixed experimental conditions were performed over the span of 100 operational runs, which showed an upward trend in the neutron production rate performance. An investigation into the impact of impurity gas in the chamber during operation showed the reduction of impurity gas in the system and an increase in neutron production rate are correlated. An estimation of the neutron production rate increase over these runs due to embedded fusion reactions in the chamber wall showed a fuel density build up near the surface by the implantation of fast neutral deuterium particles leaving the system can plausibly account for the upward trend in neutron production rate measurements. Parametric studies measured the neutron production rate with variations in the device cathode voltage (10-200 kV), cathode current (30-100 mA) and chamber pressure (0.2-1.7 mTorr D2), and comparisons with a theoretical model are made. The results of this study showed the neutron production rate scales linearly with current as expected with a beam-target fusion regime and scales in a complex manner with voltage and pressure. Comparisons made to a theoretical model of the neutron production rate using an integral transport code showed the absolute neutron production rate prediction by the model is a factor of 7.8 lower than experimental measurements. A new record for steady-state D-D neutron production rate of 3.8x108 neutrons/s has been achieved in a gridded IEC device at a cathode voltage of 200 kV, cathode current of 100 mA, and chamber pressure of 1.0 mTorr D2.

Inertial Electrostatic Confinement (IEC) Fusion
Inertial Electrostatic Confinement (IEC) Fusion

Author: George H. Miley

Publisher: Springer Science & Business Media

Published: 2013-12-12

Total Pages: 415

ISBN-13: 1461493382

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This book provides readers with an introductory understanding of Inertial Electrostatic Confinement (IEC), a type of fusion meant to retain plasma using an electrostatic field. IEC provides a unique approach for plasma confinement, as it offers a number of spin-off applications, such as a small neutron source for Neutron Activity Analysis (NAA), that all work towards creating fusion power. The IEC has been identified in recent times as an ideal fusion power unit because of its ability to burn aneutronic fuels like p-B11 as a result of its non-Maxwellian plasma dominated by beam-like ions. This type of fusion also takes place in a simple mechanical structure small in size, which also contributes to its viability as a source of power. This book posits that the ability to study the physics of IEC in very small volume plasmas makes it possible to rapidly investigate a design to create a power-producing device on a much larger scale. Along with this hypothesis the book also includes a conceptual experiment proposed for demonstrating breakeven conditions for using p-B11 in a hydrogen plasma simulation. This book also: Offers an in-depth look, from introductory basics to experimental simulation, of Inertial Electrostatic Confinement, an emerging method for generating fusion power Discusses how the Inertial Electrostatic Confinement method can be applied to other applications besides fusion through theoretical experiments in the text Details the study of the physics of Inertial Electrostatic Confinement in small-volume plasmas and suggests that their rapid reproduction could lead to the creation of a large-scale power-producing device Perfect for researchers and students working with nuclear fusion, Inertial Electrostatic Confinement (IEC) Fusion: Fundamentals and Applications also offers the current experimental status of IEC research, details supporting theories in the field and introduces other potential applications that stem from IEC.

Improved Lifetimes and Synchronization Behavior in Multi-grid Inertial Electrostatic Confinement Fusion Devices
Improved Lifetimes and Synchronization Behavior in Multi-grid Inertial Electrostatic Confinement Fusion Devices

Author: Thomas John McGuire

Publisher:

Published: 2007

Total Pages: 254

ISBN-13:

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A high output power source is required for fast, manned exploration of the solar system, especially the outer planets. Travel times measured in months, not years, will require high power, lightweight nuclear systems. The mature nuclear concepts of solidcore fission and fusion Tokamaks do not satisfy the lightweight criteria due to massive radiators and magnets respectively. An attractive alternative is Inertial Electrostatic Confinement fusion. This extremely lightweight option has been studied extensively and to date has produced significant fusion rates of order 1010 reactions per second, but at low power gains, no higher than Q = 10-4. The major loss mechanisms for the state-of-the-art IEC are identified via a detailed reaction rate scaling analysis. The use of a single cathode grid causes short ion lifetimes and operation at high device pressure for simple ion generation both fundamentally limit the efficiency of these devices. Several improvements, including operation at much lower pressure with ion guns and the use of multiple cathode grids, are verified with particle-in-cell modeling to greatly improve the efficiency of IECs. These simulations show that the greatly increased confinement allows for the development of significant collective behavior in the recirculating ions. The plasma self-organizes from an initially uniform state into a synchronized, pulsing collection of ion bunches.

A Method for Active Space Charge Neutralization in an Inertial Electrostatic Confinement (IEC) Nuclear Fusion Device
A Method for Active Space Charge Neutralization in an Inertial Electrostatic Confinement (IEC) Nuclear Fusion Device

Author: Brendan Sporer

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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Recent inertial electrostatic confinement (IEC) fusion concepts are discussed and their shortcomings noted. Ion space charge is substantiated as a significant hindrance to high efficiencies, so a method for space charge neutralization in an ion-injected IEC device is proposed. An electrostatically- plugged magnetic trap is used to confine electrons in the core region of a planar electrostatic trap for ions. The electrons act to dynamically neutralize the space charge created by converging ions for the purpose of increasing achievable core density and fusion rates. An electrostatic trap utilizing this method of neutralization is termed the plasma-core planar electrostatic trap, or PCPET. COMSOL Multiphysics 4.3 is used to model the electromagnetic fields of the PCPET and compute lone ion and electron trajectories within them. In the proper configuration, ions are shown to be stably confined in the trap for many hundreds of oscillations, potentially much longer. Electrons are confined virtually infinitely in the central electrostatically-plugged cusp. For both species, upscatter into source electrodes seems to be the dominant loss mechanism. Adjusting the electron energy and behavior in the core to provide the optimum neutralization for ions is discussed. Ion synchronization behavior can be controlled with RF signals applied to the anode. Two operational modes are identified and discriminated by the state of ion synchronization. Further experimentation is needed to determine which mode produces the optimal neutralization and fusion rate. An experimental prototype PCPET is constructed out of 3D-printed PLA and machined aluminum.

Plasma Science
Plasma Science

Author: National Academies of Sciences Engineering and Medicine

Publisher:

Published: 2021-02-28

Total Pages: 291

ISBN-13: 9780309677608

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Plasma Science and Engineering transforms fundamental scientific research into powerful societal applications, from materials processing and healthcare to forecasting space weather. Plasma Science: Enabling Technology, Sustainability, Security and Exploration discusses the importance of plasma research, identifies important grand challenges for the next decade, and makes recommendations on funding and workforce. This publication will help federal agencies, policymakers, and academic leadership understand the importance of plasma research and make informed decisions about plasma science funding, workforce, and research directions.