[en] Fusion offers the potential for a very high specific power, providing a large specific impulse that can be traded-off with thrust for mission optimization. Thus fusion is a leading candidate for missions beyond the moon. A new approach is discussed for space fusion power, namely Inertial Electrostatic Confinement (IEC). This method offers a high power density in a relatively small, simple device. It appears capable of burning aneutronic fuels which are most desirable for space applications and is well suited for direct conversion. An experimental device to test the concept is described

[en] A collimated proton detector has been developed for spatially resolved proton measurement in SEIC deuterium fusion experiments. The results are used to infer the potential well depth and well dynamics during SEIC operation. The SEIC operates as follows: ions enter the cathode-grid and are decelerated due to the presence of the positive space charge in the center created by the high ion density there. Since the fusion cross-section is ion-velocity dependent, the greater the height of the positive potential, the lower is the fusion reaction rate in that region. This source profile is determined by the collimated proton measurement. Analysis of the observed proton energy and parametric dependence on voltage current indicates that beam-background fusion predominantly occurs (for a typical 12-mA cathode current, 30-kV cathode voltage in a 4-mTorr D, background). Computer simulations suggest that for these parameters, a positive space charge potential of magnitude about 1/2 of the applied voltage forms inside the cathode. These results establish the first measurement of a positive potential well structure inside an ion injected SEIC device. The dynamics of the well profile with changing injected current is described along with a description of the technique used for unfolding the proton data

[en] Electrostatic-Inertial Confinement offers several significant advantages, including a highly non-Maxwellian plasma which is capable of burning advanced fuels, a relatively simple structure capable of high power density, and a natural connection to direct energy conversion. The plasma is confined in an electrostatic well that is created by injecting electrons through a semi-transparent, high voltage, grid type anode in spherical geometry. Oscillation of the electrons about the anode forms a negative potential well that provides effective confinement of injection high-energy ions. As the ions pass back and forth on trajectories through the center of the device, a very high density central reaction core region is formed

[en] There is considerable demand in the scientific community for a neutron generator with an output of 10⁵-10⁶ n/s that can be turned on or off, emits fusion neutrons, is self-calibrating, and can offer portable operation. This paper will describe how an IEC-based neutron generator could satisfy these demands. Experimental data and modeling is presented for operation to the 10⁵ n/s range. Direct extrapolation of the results indicate that with modest extension of operating parameters operation can be achieved in the 10⁶ - 10⁷ n/s range; with more aggressive modifications operation in the 10^8-10 n/s range can be possible

[en] A nuclear fission reactor design concept is developed to address five very stringent design criteria. A hypothesis is presented, that a local minimum in overall cost will be realized, if all design criteria that affect reactor economy are weighted equally, and a design meeting the criteria can be developed. The design criteria address reactor safety, proliferation risk, fuel utilization, conversion diversity, and weapon usable special nuclear material (SNM) disposition for both excess weapon materials, and spent reactor fuel materials. The initial design study indicates existing reactors cannot meet the criteria without substantial technological break-through. The attributes of each type of reactor that either prevent or allow it to meet one or more design criterion are presented. Mutually exclusive attributes for meeting design criteria are discarded. The most sensitive parameter is determined to be the fuel. A molten solution of pure metal aluminum, plutonium and uranium is determined to have outstanding potential to meet ail criteria. The results of two preliminary neutronic evaluations are presented, and indicate that the concept can meet the design criteria from a neutronic view. Three additional neutronic models are proposed to complete the preliminary neutronic analysis. Future materials and thermal-hydraulic research is proposed

[en] Fusion offers the potential for a very high specific power, providing a large specific impulse that can be traded-off with thrust for mission optimization. Thus fusion is a leading candidate for missions beyond the moon. Here we discuss a new approach for space fusion power, namely Inertial-Electrostatic Confinement (IEC). This method offers a high power density in a relatively small, simple device. It appears capable of burning aneutronic fuels which are most desirable for space applications and is well suited for direct energy conversion

[en] This paper concerns the development of a neutron so based on the inertial electrostatic confinement (IEC) of a low density fusion plasma in a gridded, spherically-focusing device. With the motivation of using such sources for nondestructive evaluation (NDE) applications, the focus of the development is on : Small size devices, sealed operation with D₂ or D₂/T₂ mixtures, Power-utilization and neutron-output optimization, and integration into an assay system. In this paper, we describe an experimental system that has been established for the development and testing of IEC neutron sources, and we present preliminary results of tests conducted for 25-cm and 15-cm diameter IEC devices

[en] This paper assesses the capabilities of existing computer models for Inertial-Electrostatic Confinement (IEC) systems in both the glow discharge mode of operation and the low-pressure, multiple-grid systems. A comparison is made of the present computer simulations of generic IEC devices to today's running gridded-IEC experiments, based on assumptions used in the models to the physical parameters of the experiments. The pros and cons of such an approach is argued, and a list of critical parameters for a more realistic solution is offered. In addition, an alternate approach to developing a self-consistent model for these modes of operation with gridded systems is proposed

[en] A collimated proton detector has been developed for spatial resolved proton measurements in inertial-electrostatic plasma confinement (IEC) fusion experiments. These are the first proton measurements used to infer potential well profiles on an IEC device. This paper describes a new technique for investigating the existence of multiple potential wells inside IEC devices. Analysis of the observed proton energy and source profile indicates that (for a 12-mA cathode current, a 30-kV cathode voltage in a 4-mTorr D₂ background) predominantly beam-background fusion occurs. Computer simulation suggests that a positive space charge potential approximately half that of the applied voltage is formed inside the cathode. These results establish the first measurement of a positive potential well structure inside an ion-injected IEC device

[en] Two different, complementary approaches were taken to determine the effects of an Inertial Electrostatic Confinement (IEC) grid's design on the neutron production rate of the device. A semi-empirical formula developed from experimental data predicts the neutron yield of an IEC device, given the chamber size, grid radius and transparency, and operating voltage and current. Results from the IXL computer program support some of the scalings found in the semi-empirical formula. A second formula was also developed that predicts the neutron yield of an IEC device using grid design parameters and the ion core radius. The SIMION computer program was used to calculate the ion core radius. These formulas are useful tools for designing grids that will maximize the neutron yield for IEC devices. 7 refs., 9 figs