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Title: Space Propulsion Based on Dipole Assisted IEC System

Abstract

A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion propulsion exists by introducing a magnetic dipole into the IEC chamber. The dipole fields should increase the plasma density, hence fusion rate, in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC (DaIEC) configuration can provide improved confinement vs. a stand alone IEC, a first model DaIEC experiment has been benchmarked against a reference IEC. A triple Langmuir probe was used to measure the electron temperature and density. It was confirmed that the magnetic field increases the electron density by an order of magnitude and the addition of a controlled electrical potential to the dipole structure allows control of space charge buildup in the dense core region. This paper describes the dipole assisted IEC concept, its advantages, and soon missions it is well suited for. Here the present status of DaIEC experiments are described, the issues for scale up are discussed, and a conceptual plan for a power unit development is presented.

Authors:
; ;  [1]; ;  [2]
  1. Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801 (United States)
  2. NPL Associates Inc. 912 W. Armory, Champaign, IL, 61821 (United States)
Publication Date:
OSTI Identifier:
20797974
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 813; Journal Issue: 1; Conference: 10. conference on thermophysics applications in microgravity; 23. symposium on space nuclear power and propulsion; 4. conference on human/robotic technology and the national vision for space exploration; 4. symposium on space colonization; 3. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 12-16 Feb 2006; Other Information: DOI: 10.1063/1.2169307; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONTROL; ELECTRON DENSITY; ELECTRON TEMPERATURE; INERTIAL CONFINEMENT; LANGMUIR PROBE; MAGNETIC DIPOLES; MAGNETIC FIELDS; PLASMA; PLASMA DENSITY; PROPULSION; SPACE CHARGE; THERMONUCLEAR REACTORS

Citation Formats

Miley, George H., Thomas, Robert, Takeyama, Yoshikazu, Momota, Hiromu, and Shrestha, Prajakti J.. Space Propulsion Based on Dipole Assisted IEC System. United States: N. p., 2006. Web. doi:10.1063/1.2169307.
Miley, George H., Thomas, Robert, Takeyama, Yoshikazu, Momota, Hiromu, & Shrestha, Prajakti J.. Space Propulsion Based on Dipole Assisted IEC System. United States. doi:10.1063/1.2169307.
Miley, George H., Thomas, Robert, Takeyama, Yoshikazu, Momota, Hiromu, and Shrestha, Prajakti J.. Fri . "Space Propulsion Based on Dipole Assisted IEC System". United States. doi:10.1063/1.2169307.
@article{osti_20797974,
title = {Space Propulsion Based on Dipole Assisted IEC System},
author = {Miley, George H. and Thomas, Robert and Takeyama, Yoshikazu and Momota, Hiromu and Shrestha, Prajakti J.},
abstractNote = {A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion propulsion exists by introducing a magnetic dipole into the IEC chamber. The dipole fields should increase the plasma density, hence fusion rate, in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC (DaIEC) configuration can provide improved confinement vs. a stand alone IEC, a first model DaIEC experiment has been benchmarked against a reference IEC. A triple Langmuir probe was used to measure the electron temperature and density. It was confirmed that the magnetic field increases the electron density by an order of magnitude and the addition of a controlled electrical potential to the dipole structure allows control of space charge buildup in the dense core region. This paper describes the dipole assisted IEC concept, its advantages, and soon missions it is well suited for. Here the present status of DaIEC experiments are described, the issues for scale up are discussed, and a conceptual plan for a power unit development is presented.},
doi = {10.1063/1.2169307},
journal = {AIP Conference Proceedings},
number = 1,
volume = 813,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2006},
month = {Fri Jan 20 00:00:00 EST 2006}
}
  • Earlier conceptual design studies (Bussard, 1990; Miley et al., 1998; Burton et al., 2003) have described Inertial Electrostatic Confinement (IEC) fusion propulsion to provide a high-power density fusion propulsion system capable of aggressive deep space missions. However, this requires large multi-GW thrusters and a long term development program. As a first step towards this goal, a progression of near-term IEC thrusters, stating with a 1-10 kWe electrically-driven IEC jet thruster for satellites are considered here. The initial electrically-powered unit uses a novel multi-jet plasma thruster based on spherical IEC technology with electrical input power from a solar panel. In thismore » spherical configuration, Xe ions are generated and accelerated towards the center of double concentric spherical grids. An electrostatic potential well structure is created in the central region, providing ion trapping. Several enlarged grid opening extract intense quasi-neutral plasma jets. A variable specific impulse in the range of 1000-4000 seconds is achieved by adjusting the grid potential. This design provides high maneuverability for satellite and small space probe operations. The multiple jets, combined with gimbaled auxiliary equipment, provide precision changes in thrust direction. The IEC electrical efficiency can match or exceed efficiencies of conventional Hall Current Thrusters (HCTs) while offering advantages such as reduced grid erosion (long life time), reduced propellant leakage losses (reduced fuel storage), and a very high power-to-weight ratio. The unit is ideally suited for probing missions. The primary propulsive jet enables delicate maneuvering close to an object. Then simply opening a second jet offset 180 degrees from the propulsion one provides a 'plasma analytic probe' for interrogation of the object.« less
  • A preliminary system design is presented for a high performance 100-MWe manned space vehicle in the 500 metric ton class, based on Inertial Electrostatic Fusion (IEC), allowing trip times to the outer planets of several months. An IEC is chosen because it's simplified structure results in a very high power-to-weight ratio. D-{sup 3}He fuel is used to give 14.7-MeV protons as a primary fusion reaction product. Direct conversion of proton energy to electricity is employed, providing a high efficiency. An IEC reactor with a proton energy gain (power in 14.7-MeV protons/input electric power) of 4 or better is assumed. Extrapolationmore » of present laboratory scale IEC experiments to such conditions is possible theoretically, but faces several open issues that require further study such as stability under high-density conditions. The final thruster is based on an NSTAR-extrapolated krypton ion design with a specific impulse of 16,000 seconds and a total thrust of 1020 N. Round trip thrust time for mission set to Jupiter {delta}V of 100 km/s is then {approx}950 days. (authors)« less
  • In this paper, the unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configuration as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of 1 kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in 1 yr and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 yr. This is about ten times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power towardmore » 10 kW/kg are discussed, as is an approach to implementing the concept through proof testing on the moon.« less
  • United States missile projects, goahs, and budget aspects are discussed. Missile guidance and control systems are described, and data acquisition methods and equipment are explained. Propulsion and power generation, especially that derived from nuclear and electrical devices, are discussed. Finally, earth-based electronic devices which are important in missile operations are described. (L.N.N.)
  • 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 {ital et al.} 1995a). In the interests of space power and propulsion systems, conceptual rocket design studies (Bussard and Jameson 1994, Miley {ital 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 recentmore » survey of prior conceptual design studies of fusion rockets, Williams and Borowski (1997) found that the Bussard IEC conceptual study (the {open_quotes}QED{close_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} {ital 1998 American Institute of Physics.}« less