[en] Inertial electrostatic confinement (IEC) fusion confines high energy ions in potential wells, where their increased energy and density yields a high fusion rate. Studies of the IEC at the University of Illinois (UI) initially concentrated on steady-state operation where neutron yields of approx.10⁶ D-D n/s are routinely obtained. However, the development of a pulsed configuration has been undertaken to provide higher neutron yields. Preliminary experiments have demonstrated I² scaling during pulsed operation when the perveance threshold of 2.2 mA/kV^3/2 is exceeded. Based on these results, it appears that the present IEC could be operated with 3-A, 100-kV repetitive pulses with a 10% duty factor to produce neutron yields of approx.10¹⁰ neutrons/second. 6 refs., 7 figs

[en] Inertial electrostatic confinement (IEC) offers a unique plasma target neutron source. Deuteron ions are accelerated, producing fusion reactions as they react with a deuterium plasma target. Current devices offer 10⁶ to 10⁷ 2.5-MeV deuterium-deuterium (D-D) n/s during steady-state operation. Conversion to higher energy (14-MeV) neutrons by substituting deuterium-tritium (D-T) fill gas gives 10⁸ to 10⁹ D-T n/s. Higher yield (> 10⁹ D-D n/s time averaged) pulsed versions are under development. Consequently, the IEC neutron source is currently competitive, in neutron strength, with ²⁵²Cf and with small accelerator solid-target sources. Further, it offers a number of advantages, including an on-off capability, long lifetime (avoiding target deterioration or radioactive decay), and minimum radioactivity involvement. These features simplify IEC usage and ease licensing restrictions. For these reasons, the IEC provides an excellent laboratory neutron source and an attractive, cost-efficient industrial source for neutron activation analysis and nondestructive testing

[en] Inertial Electrostatic Confinement (IEC) is a unique approach to fusion and plasma energy systems that was conceptualized in the 1960s (Hirsch 1967) and has been the focus of recent development in the 1990s (Miley et al. 1995a). In the interests of space power and propulsion systems, conceptual rocket design studies (Bussard and Jameson 1994, Miley et al. 1995b) using the IEC have predicted excellent performance for a variety of space missions, since the power unit avoids the use of magnets and heavy drives resulting in a very high, specific impulse compared to other fusion systems. In their recent survey of prior conceptual design studies of fusion rockets, Williams and Borowski (1997) found that the Bussard IEC conceptual study (the ''QED'' engine) offered a thrust-to-weight ratio of 10 milli-g's, a factor of five higher than conventional magnetic confinement concepts and even slightly above anti-proton micro fission/fusion designs. Thus there is considerable motivation to study IEC concepts for eventual space applications. However, the physics feasibility of the IEC still requires experimental demonstration, and an expanded data base is needed to insure that a power unit can in fact be built

[en] Inertial Electrostatic Confinement (IEC) is a unique approach to fusion and plasma energy systems that was conceptualized in the 1960s (Hirsch 1967) and has been the focus of recent development in the 1990s (Miley et al. 1995a). In the interests of space power and propulsion systems, conceptual rocket design studies (Bussard and Jameson 1994, Miley et al. 1995b) using the IEC have predicted excellent performance for a variety of space missions, since the power unit avoids the use of magnets and heavy drives resulting in a very high, specific impulse compared to other fusion systems. In their recent survey of prior conceptual design studies of fusion rockets, Williams and Borowski (1997) found that the Bussard IEC conceptual study (the open-quotes QEDclose quotes engine) offered a thrust-to-weight ratio of 10 milli-g close-quote s, a factor of five higher than conventional magnetic confinement concepts and even slightly above anti-proton micro fission/fusion designs. Thus there is considerable motivation to study IEC concepts for eventual space applications. However, the physics feasibility of the IEC still requires experimental demonstration, and an expanded data base is needed to insure that a power unit can in fact be built. copyright 1998 American Institute of Physics

[en] A novel plasma jet thruster, based on Inertial Electrostatic Confinement (IEC) technology, is described for orbit transfer operations. While electronically driven, it represents a fore summer of a future fusion powered unit. The IEC thruster employs a spherical configuration, wherein ions are generated and accelerated towards the center of a spherical vacuum chamber where a high-density central core region accelerated ions into an intense quasi-neutral ion jet. Compared to other high-power plasma thrusters, the IEC offers advantages in design simplicity and minimum propellant leakage, plus a high power-to-weight ratio. (authors)

[en] A cylindrical version of the single grid Inertial Electrostatic Confinement (IEC) device (termed the C-device) has been developed for use as a 2.5-MeV D-D fusion neutron source for neutron activation analysis. The C-device employs a hollow-tube type cathode with similar anodes backed up by ''reflector'' dishes. The resulting discharge differs from a conventional hollow cathode discharge, by creating an explicit ion beam which is ''pinched'' in the cathode region. Resulting fusion reactions generate ∼10⁶ neutron/s. A pulsed version is under development for applications requiring higher fluxes. Several pulsing techniques are under study, including an electron emitter (e-emitter) assisted discharge in a thorated tungsten wire emitter located behind a slotted area in the reflector dishes. Pulsing is initiated after establishing a low power steady-state discharge by pulsing the e-emitter current using a capacitor switch type circuit. The resulting electron jet, coupled with the discharge by the biased slot array, creates a strong pulse in the pinched ion beam. The pulse length/repetition rate are controlled by the e-emitter pulse circuit. Typical parameters in present studies are ∼30micros, 10Hz and 1-amp ion current. Corresponding neutron measurements are an In-foil type activation counter for time averaged rates. Results for a wide variety of operating conditions are presented

[en] We measured the number of the neutrons and protons produced by D-D reactions in an accelerated beam-plasma fusion and carried out the numerical simulations. The linear dependence of the neutron yield on a discharge current indicates that the fusion reactions occur between the background gas and the fast particles, i.e. charge exchanged neutrals and accelerated ions. The neutron yield divided by (fusion cross section x ion current x neutral gas pressure) still possesses the dependence of the 1.2 power of discharge voltage, which shows the fusion reactions are affected by the electrostatic potential built-up in the center. The measured proton birth profiles suggest the existence of a double potential well, which is supported by the numerical simulations. (author)

No abstract available

[en] We measured the number of the neutrons and protons produced by D-D reactions in an accelerated beam-plasma fusion and curried out the numerical simulations. The linear dependence of the neutron yield on a discharge current indicates that the fusion reactions occur between the background gas and the fast particles. i.e. charge exchanged neutrals and accelerated ions. The neutron yield divided by (fusion cross section x ion current x neutral gas pressure) still possesses the dependence of the 1.2 power of discharge voltage. which shows the fusion reactions are affected by the electrostatic potential built-up in the center. The measured proton birth profiles suggest the existence of a double potential well, which is supported by the numerical simulations. (author)

[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