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Hydrodynamic problems of reactor containment
Abstracts single arbitrary function.’ The special case p’ (y) = w + b, f(y) = q + d is linear and allows complete integration of the equations by expansion in some geometries. Equation (1) can be shown to be the Euler equation of the variational function J(BZ/2p - p) dV provided that suitable admissible classes of B andp are selected. Using this approach a large variety of existence theorems of the type previously mentioned can be conjectured and also many of an entirely different nature, for example, in a toroidal geometry in which B-lines do not intersect any external boundary on which “initial” values ofp or J,, can be specified.2 It might be remarked that the practical significance of such existence theorems lies in the expectation that any solution of (1) can be realized by displaying sufficient experimental ingenuity, provided that it is in some sense stable. 1 This has also been observed by HAROLD FURTH. 2 Similar conjectures have been made by M. D. KRUSKAL.
P/387. Microwave Studies of Gas Discharge Plasmas. SANBORN C. BROWN (U.S.A.). The interaction of microwave electromagnetic radiation and the plasma of gas discharges has been the subject of a great deal of research for many years. A survey of the usefulness of this technique as applied to intensely ionized plasmas will be presented. Particular attention will be given to the microwave technique as a diagnostic tool in determining plasma densities including a survey of the various types of microwave probes and their experimental limitations. The use of microwave power does not appear likely to produce high-density plasmas; however, stable low-pressure microwave plasmas in magnetic fields provide a good method for measuring the fundamental behaviour of gas discharge phenomena of interest in controlled thermonuclear plasmas, and studies along these lines will be reported. The applicability of the microwave method in studying electron collision crosssections, recombination and diffusion processes in magnetic fields will also be discussed. Hydrodynamic Problems of Reactor P/434. Containment. F. B. PORZEL (U.S.A.). This paper summarizes briefly the main features of some hydrodynamic problems in the design of reactors for containment against internal explosions. The material comprises work at the Armour Research Foundation of the Illinois Institute of Technology during the past two years both in general studies, theoretical and experimental, and in the analyses of many specific reactors. The pertinent conclusions which summarize this experience are as follows and apply to explosions in various solid and liquid media: the Rankine-Hugoniot equations are of general
285
applicability to both shocks and strong pressure pulses; a large pressure change across a shock (thousands of bars) is equivalent to a small temperature rise (few degrees); a “waste heat concept” is employed both for conservation of energy and as a model for the bona fide dissipation of energy across a shock front; only a small fraction (like 1%) of the total energy appears as mechanical energy at long distances of practical interest from an explosion; the peakpressure P versus distance R curve falls rapidly close-in (P -R-T) until the dynamic crushing strength of the material is reached; the peakpressure of the shock and the gradient behind it are so related that the total energy is relatively insensitive to the wave shape; there is an enormous preference for hydiodynamic energy to flow into rarefied media (like 1000 : 11. Based on these hydrodynamic consideiations, two techniques of reactor containmeni have been found most effective; a composite “blast shield” which effects an optimum conversion of mechanical energy to thermal energy by choice of specific materials (steel, wood, foam plastics) and a geometrical design; and through “channelling” which directs the blast energv awav, from critical structures and dissipates it”;nnocuously over a large volume. Three other techniques of containme:t usually prove disappointing: lengthening the duration of the energy release. isolation bv air gaps and reflecting b&iers. Hydrodynami: reasons are shown for the failure of these latter methods. P/1025. Low Voltage-gradient Pinches in Metal Walled Systems. G. A. SAWYER and T. F. STRATTON
(U.S.A.).
Studies were made of high current pinched discharges in deuterium gas. Voltage gradients were one to five volts per cm, initial gas pressures were 0.1 to 10 microns Hg and axial magnetic fields were 500 gauss maximum. Metal walled, linear discharge tubes of 15 cm diameter and 90 cm diameter were investigated. The 15 cm diameter tube was also assembled as an electrodeless, endless square with elbows at the corners, and excited as an air-core transformer. Currentvoltage characteristics, high speed photography, time-resolved spectra and magnetic probe measurements were the principal diagnostic techniques. The magnetic field distributions obtained with the magnetic probes showed an oscillation in time and space for certain combinations of gas density, gas current and applied axial magnetic field. It was possible to derive complete current distributions in this case from the time and radial dependence of the three components of magnetic field. The current distribution was found to show a helical notch of reduced current density which rotated with uniform angular velocity. The helical regularity appeared to be a superposition of hydromagnetic waves of
P/387. Microwave Studies of Gas Discharge Plasmas. SANBORN C. BROWN (U.S.A.). The interaction of microwave electromagnetic radiation and the plasma of gas discharges has been the subject of a great deal of research for many years. A survey of the usefulness of this technique as applied to intensely ionized plasmas will be presented. Particular attention will be given to the microwave technique as a diagnostic tool in determining plasma densities including a survey of the various types of microwave probes and their experimental limitations. The use of microwave power does not appear likely to produce high-density plasmas; however, stable low-pressure microwave plasmas in magnetic fields provide a good method for measuring the fundamental behaviour of gas discharge phenomena of interest in controlled thermonuclear plasmas, and studies along these lines will be reported. The applicability of the microwave method in studying electron collision crosssections, recombination and diffusion processes in magnetic fields will also be discussed. Hydrodynamic Problems of Reactor P/434. Containment. F. B. PORZEL (U.S.A.). This paper summarizes briefly the main features of some hydrodynamic problems in the design of reactors for containment against internal explosions. The material comprises work at the Armour Research Foundation of the Illinois Institute of Technology during the past two years both in general studies, theoretical and experimental, and in the analyses of many specific reactors. The pertinent conclusions which summarize this experience are as follows and apply to explosions in various solid and liquid media: the Rankine-Hugoniot equations are of general
285
applicability to both shocks and strong pressure pulses; a large pressure change across a shock (thousands of bars) is equivalent to a small temperature rise (few degrees); a “waste heat concept” is employed both for conservation of energy and as a model for the bona fide dissipation of energy across a shock front; only a small fraction (like 1%) of the total energy appears as mechanical energy at long distances of practical interest from an explosion; the peakpressure P versus distance R curve falls rapidly close-in (P -R-T) until the dynamic crushing strength of the material is reached; the peakpressure of the shock and the gradient behind it are so related that the total energy is relatively insensitive to the wave shape; there is an enormous preference for hydiodynamic energy to flow into rarefied media (like 1000 : 11. Based on these hydrodynamic consideiations, two techniques of reactor containmeni have been found most effective; a composite “blast shield” which effects an optimum conversion of mechanical energy to thermal energy by choice of specific materials (steel, wood, foam plastics) and a geometrical design; and through “channelling” which directs the blast energv awav, from critical structures and dissipates it”;nnocuously over a large volume. Three other techniques of containme:t usually prove disappointing: lengthening the duration of the energy release. isolation bv air gaps and reflecting b&iers. Hydrodynami: reasons are shown for the failure of these latter methods. P/1025. Low Voltage-gradient Pinches in Metal Walled Systems. G. A. SAWYER and T. F. STRATTON
(U.S.A.).
Studies were made of high current pinched discharges in deuterium gas. Voltage gradients were one to five volts per cm, initial gas pressures were 0.1 to 10 microns Hg and axial magnetic fields were 500 gauss maximum. Metal walled, linear discharge tubes of 15 cm diameter and 90 cm diameter were investigated. The 15 cm diameter tube was also assembled as an electrodeless, endless square with elbows at the corners, and excited as an air-core transformer. Currentvoltage characteristics, high speed photography, time-resolved spectra and magnetic probe measurements were the principal diagnostic techniques. The magnetic field distributions obtained with the magnetic probes showed an oscillation in time and space for certain combinations of gas density, gas current and applied axial magnetic field. It was possible to derive complete current distributions in this case from the time and radial dependence of the three components of magnetic field. The current distribution was found to show a helical notch of reduced current density which rotated with uniform angular velocity. The helical regularity appeared to be a superposition of hydromagnetic waves of