Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
A one-dimensional magnetohydrodynamic computer code has been developed to study magnetic flux compression using explosively driven plasma armatures in cylindrically symmetric systems. This work supports a program to develop a compact, non-destructive, repetitive pulse power generator capable of multimegajoule outputs with pulse widths of about 10−5 sec. Details of the code construction and results of some calculations including the cynamics of the explosive detonation are presented.
Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781720618492 Category : Languages : en Pages : 38
Book Description
Magnetic flux compression reaction chambers offer considerable promise for controlling the plasma flow associated with various micronuclear/chemical pulse propulsion and power schemes, primarily because they avoid thermalization with wall structures and permit multicycle operation modes. The major physical effects of concern are the diffusion of magnetic flux into the rapidly expanding plasma cloud and the development of Rayleigh-Taylor instabilities at the plasma surface, both of which can severely degrade reactor efficiency and lead to plasma-wall impact. A physical parameter of critical importance to these underlying magnetohydrodynamic (MHD) processes is the magnetic Reynolds number (R(sub m), the value of which depends upon the product of plasma electrical conductivity and velocity. Efficient flux compression requires R(sub m) less than 1, and a thorough understanding of MHD phenomena at high magnetic Reynolds numbers is essential to the reliable design and operation of practical reactors. As a means of improving this understanding, a simplified laboratory experiment has been constructed in which the plasma jet ejected from an ablative pulse plasma gun is used to investigate plasma armature interaction with magnetic fields. As a prelude to intensive study, exploratory experiments were carried out to quantify the magnetic Reynolds number characteristics of the plasma jet source. Jet velocity was deduced from time-of-flight measurements using optical probes, and electrical conductivity was measured using an inductive probing technique. Using air at 27-inHg vacuum, measured velocities approached 4.5 km/s and measured conductivities were in the range of 30 to 40 kS/m.Turner, M. W. and Hawk, C. W. and Litchford, R. J.Marshall Space Flight CenterELECTRICAL RESISTIVITY; PLASMA COMPRESSION; MAGNETIC FLUX; REYNOLDS NUMBER; PLASMA JETS; PLASMA DYNAMICS; STABILITY; CHEMICAL PROPULSION; SPACECRAFT PROPULSION; ARMATURES; TEST FACILITIES; PLASMA GUNS
Author: M. W. Turner Publisher: ISBN: Category : Magnetic flux Languages : en Pages : 29
Book Description
Magnetic flux compression reaction chambers offer considerable promise for controlling the plasma flow associated with various micronuclear/chemical pulse propulsion and power schemes, primarily because they avoid thermalization with wall structures and permit multicycle operation modes. The major physical effects of concern are the diffusion of magnetic flux into the rapidly expanding plasma cloud and the development of Rayleigh-Taylor instabilities at the plasma surface, both of which can severely degrade reactor efficiency and lead to plasma-wall impact. A physical parameter of critical importance to these underlying magnetohydrodynamic (MHD) processes is the magnetic Reynolds number (Rm), the value of which depends upon the product of plasma electrical conductivity and velocity. Efficient flux compression requires Rm”1, and a thorough understanding of MHD phenomena at high magnetic Reynolds numbers is essential to the reliable design and operation of practical reactors. As a means of improving this understanding, a simplified laboratory experiment has been constructed in which the plasma jet ejected from an ablative pulse plasma gun is used to investigate plasma armature interaction with magnetic fields. As a prelude to intensive study, exploratory experiments were carried out to quantify the magnetic Reynolds number characteristics of the plasma jet source. Jet velocity was deduced from time-of-flight measurements using optical probes, and electrical conductivity was measured using an inductive probing technique. Using air at 27-inHg vacuum, measured velocities approached 4.5 km/s and measured conductivities were in the range of 30 to 40 kS/m.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The PULSAR concept of inductive pulsed power source uses a flux-compressing metallic or plasma armature rather than a fast opening switch to transfer magnetic flux to a load. The inductive store may be a relatively unsophisticated dc superconducting magnet since no magnetic energy is taken from it, and no large current transients are induced in it. Initial experimental efforts employed either expendable or reusable metallic armatures with a 200 kJ, 450 mm diameter superconducting magnet. Attention is now being focused on the development of much faster plasma armatures for use in larger systems of one and two meters diameter. Techniques used to generate the required high magnetic Reynolds number flow will be described and initial experimental results will be presented.
Author: Peter J. Turchi Publisher: Springer Science & Business Media ISBN: 1468410482 Category : Science Languages : en Pages : 666
Book Description
The generation and use of megagauss magnetic fields have been subjects of research and development in laboratories around the world for over a quarter of a century. Research goals have included the development of compact, short-pulse, electrical power sources and the production of ultrahigh magnetic field strengths over significant experimental volumes. Energies measured in megajoules, currents in megamperes and timescales of microseconds are not uncommon in such work. Phase changes, insulator breakdowns, and local des truction of the apparatus are also frequently encountered. Some efforts have involved the use of high explosive systems, developing methodologies rather distinct from those of a normal physics laboratory. Manipulation of magnetic flux to exchange energy between high speed, electrically conducting flows and high strength electromagnetic fields remains, of course, a basic interaction of classical physics. The remoteness of the necessary experimental sites (at least in many instances) and the various national concerns for security of defense-related research have often limited the flow of information between investigators of separate organizations, working in common areas of technical concern. Occa sionally, however, it has been possible for the community of scientists and engineers engaged in work on high magnetic fields and related high energy den sity systems to gather together and exchange results and plans, successes and failures. The first such international gathering was in 1965 at the Conference on Megagauss Magnetic Field Generation by Explosives and Related Experi ments, Frascati, Italy.
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Author: National Aeronautics and Space Administration (NASA)
Author: M. W. Turner
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Author: Ron J. Litchford
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Author: Peter J. Turchi
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