The theory of Prigogine and Balescu has been applied to a homogeneous single-species plasma in a static uniform magnetic field. A kinetic equation has been obtained for the one particle velocity distribution, which is assumed initially isotropic in directions perpendicular to the field. The only stationary solutions of the kinetic equation are the Maxwellian equilibrium distributions, and an H- theorem has been established. The neglect of "collisions" of the order of duration of one cyclotron period or less (a strong magnetic field approximation) modifies the kinetic equation so that it no longer predicts any relaxation of the velocity components parallel to the magnetic field. An equation for the binary correlation function has been obtained in terms of the one particle velocity distribution, which is in turn determined toy the kinetic equation. Equations for the binary spatial correlation function and the binary correlation function for the guiding centers have also been obtained. It is demonstrated that the binary spatial correlation function represents the well-known Debye-screened equilibrium correlations when the one particle velocity distribution is the equilibrium distribution. The assumptions and approximations of the theory are clearly stated, and are discussed in some detail. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

[No abstract available] / Science, Faculty of / Chemistry, Department of / Graduate

A method is described whereby the recovery of plasmas formed by the passage of a high current discharge across a spark gap has been measured as a function of both the time after the passage of a current pulse and the radial distance from the centre of the spark gap. The effects of pressure, current magnitude and current waveform on the recovery time of the test gap were investigated and it was found that all of them exerted powerful but explicable influences on the recovery. Gas temperatures were derived using the assumption that the Paschen Law holds true during the final recovery period. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

[No abstract available] / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The conductance of a small electric probe has been determined for radial distances (2 - 15 cm) from a recovering spark gap as a function of time after discharge initiation. The times investigated were from 0.2 to 15 ms and the gas pressure was varied from 22 mmHg down to 0.1 mmHg. The voltage applied to the probes was a sawtooth pulse which rose to about 80 volts in 10 μs. It is shown theoretically that the probe conductance should be proportional to the three-halves power of the gas temperature. Prom a known value of the temperature, deduced from recovery measurements, and the known probe conductance the constant of proportionality was deduced. Hence it was possible to determine the temperature from the probe conductance. The probe conductance measurements show that at 200 mmHg pressure the spark channel is only 2 cm in radius and that there is no detectable ionization left 2 ms after the discharge. As the gas pressure decreases the spark channel increases in size and takes longer to deionize, until at 1 mmHg pressure the channel fills the whole spark chamber (spark channel radius is 15 cm) and requires almost 15 ms to deionize. At 1 mmHg gas pressure there is a radial temperature gradient, while at 0.1 mmHg pressure the gas everywhere in the channel recovers at the same rate. In this experiment it is theoretically predicted that volume recombination should be the dominant recovery method and this is experimentally verified. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis is concerned with a theoretical and experimental investigation of Alfvén waves in an ionized medium, and magnetic interaction effects between a moving plasma and a magnetic coil external to the plasma. Methods for generating Alfvén disturbances for varying conditions of gas density and magnetic fields are considered and various means for measuring any effects that may be produced. It will be seen that for propagation of m.h.d. waves, extremely strong coupling between the plasma and field is necessary with consequent necessary high fields and Alfvén speeds. The effect of an axial magnetic field modifying the shock speed in the plasma is investigated and also the effect of the field on incident and reflected shock speeds by placing a plain obstruction in the shock tube which blocks the plasma flow. A further study of magnetic interaction effects between a moving plasma and a localized radial field was undertaken with the desire of correlating mechanical momentum transfer with varying conditions of applied field and gas pressures in the plasma (hence conductivity, density, and shock speed variations). Mechanical and electrical measurements of momentum transfer are compared with theory, and it will be seen that the mechanical method offers a fairly reliable means of measurement. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Studies in the general field of gas chromatographic analysis have been made and some of the methods developed have been applied to a kinetic investigation of the reactions of methyl radicals with butene-1. In Part I the developments in the field of gas chromatography are described. An all-metal thermal conductivity cell with platinum sensing elements has been designed and constructed. Excellent compensation for the resulting changes of flow rate of the carrier gas was attained in analyses with rising column temperature. The use of thermistors as sensing elements in such cells was also studied. The influence of polarity of the stationary phase on relative retention volumes in gas partition chromatography was investigated in conjunction with the analysis of a complex mixture of organic sulfur compounds. Satisfactory separations of hydrogen sulfide, methyl mercaptan, ethyl mercaptan, methyl sulfide, propyl mercaptan, ethyl sulfide, thiophene and dimethyl disulfide were obtained. Isopentane and n-pentane were included for purposes of comparison. Irregularities were observed in relating retention volumes to boiling points for some of these compounds. Reversal of normal elution order within groups of compounds with different columns was related to the polarity of the column and the polarisability of the eluents. A high-sensitivity ionization gauge detector for gas chromatography was developed. By keeping the grid potential below the ionization potential of helium the device is sensitive only to the eluted compounds in the gas stream. Sensitivities from 100 to 500 times greater than those of thermal conductivity cells were observed. Only a small fraction of the gas stream emerging from the column is sufficient for detection purposes, and the device is insensitive to temperature and flow rate changes. Significant advantages may be obtained from the application of the newly developed ionization gauge detector to displacement chromatography because of the possibility of distinguishing between isomeric organic compounds. Results obtained with gas chromatographic methods without the use of a carrier gas are reported. A partial separation of a mixture of volatile organic compounds was obtained. The ionization gauge detector may be useful in the development of this method. In Part II the results obtained from the reaction of methyl radical with butene-1 are described. Alumina, squalane-pelletex, and tricresyl phosphate columns were used for the gas chromatographic analysis. Mass spectrometric identification of products was done where necessary. In the temperature range 160 to 220°C with di-t-butyl peroxide as the methyl source the following reaction products were identified: methane, ethane, 3-methyl-butene-1, pentene-2, n-pentane, isopentane, 3-methyl-pentane, and acetone. A mechanism accounting for the formation of these products and supported by kinetic evidence is presented. The butenyl and pentyl radicals formed in the reaction are stable near 200°C. Butenyl radical does not abstract hydrogen from butene-1 near 200°C, but combines with methyl to yield pentene-2 and 3-methyl-butene-1. The energy of activation for the formation of 3-methyl-butene-1 is from 2 to 4 kcal/mole higher than for the formation of pentene-2. Hydrogen abstraction by pentyl radicals from butene-1 gives n-pentane, and isopentane. The reactivity of the branched radical •CH₂CH[CH₃]CH₂CH₃ in hydrogen abstraction is twice as great as that of the straight chain radical CH₃CH₂CHCH₂CH₃. From material balances obtained it was found that 60 to 80% of butenyl, and from 7 to 30% of pentyl radicals are removed from the system by reactions other than combination with methyl and hydrogen abstraction in the case of pentyl. The disproportionation of pentyl radicals to pentane and pentene was unimportant in the present system. At 450 and 492°C methyl radicals do not sensitize the formation of the cyclic reaction products which were observed by other workers in the unsensitized pyrolysis of butene-1 at temperature near 500°C. The main reaction product of methyl with butene-1 at 450 and 492°C was found to be butene-2. The isomerization to butene-2 in the unsensitized reaction is a chain process with chain length increasing with temperature reduction. The mechanism of the chain reaction of isomerization is postulated to be: CH₂=CHCH₂CH₃ → CH₃ • + CH₂ = CHCH₂ • / CH₃ • + CH₂=CHCH₂CH₃ → CH₂=CHCHCH₃ + CH₄ / CH₂=CHCHCH₃ ↔ •CH₂CH=CHCH₃ / •CH₂CH=CHCH₃ + CH₂=CHCH₂CH₃ → CH₃CH=CHCH₃+ CH₂=CHCHCH₃. The chain length at 450°C was found to be 12.6, and at 492°C as 2.3. / Science, Faculty of / Chemistry, Department of / Graduate

In the work described in this thesis attempts have been made to obtain information on three aspects of the behaviour of liquid argon as an ionization counter. Ionization was produced by alpha particles from a source deposited on the negative electrode of a small parallel-plate chamber in which pure argon was liquefied. The current pulses resulting from movement of the liberated electrons in the field applied to the plates were analysed electronically. Firstly, it was desired to determine the time taken by the electrons originating from distinct ionization events to traverse measured electrode separations and be collected by the positive electrode. These transit times depend upon the electron mobility in liquid argon, defined as the velocity of the electrons per unit field. From this mobility, the mean free path and collision cross-section of the electrons with respect to argon atoms can be calculated. Some estimates of transit times and mobilities, and resulting values of mean free path and cross-section are given. However, it appears that limitations of the electrode spacing and the applied field cause the transit time to be so short as to necessitate the use of wide band amplifiers with, consequently, high noise levels. Secondly, the causes of variation in size of current pulses with angle of emission of the initiating alpha particles were investigated. The effect of greatest interest was that, due to the geometry of the chamber, as from it a determination was made of the range of alpha particles in liquid argon. For 5.3 MeV alpha particles, the weighted centre of ionization was found to be 0.006 cms. from the source, implying a particle range of about 0.009 cms. The number of electrons contributing to current pulses was also found to be a function of the angle of emission, on account of a variable degree of recombination with the positive ion column. This number was determined, and even under the most advantageous conditions fell considerably short of the probable total number liberated. This fact imposes a serious limitation on the potentialities of liquid argon as a useful counter. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A high-frequency discharge ion source was developed yielding 45% protons in an 800 microampere, 14 kv energy focused beam of positive hydrogen ions. Higher ion currents could be delivered at higher voltages. The discharge was excited in a pyrex discharge tube, 1¼ inches in diameter and 9 inches long, by a 210 Mc/sec. push-pull, oscillator capable of delivering 120 watts power. An electrostatic potential difference of 1.8 kv applied axially with the discharge tube, accelerated the positive ions formed in the discharge toward the exit canal. A magnetic field of 240 gauss, also applied axially, shaped the discharge conically, and intensified the redness of the discharge, causing the Balmer lines to appear prominently when the discharge was viewed through a spectroscope. The ions emerging from the exit canal were focused by an electrostatic lens using a potential difference of 12 kv. The hydrogen pressure in the discharge tube measured 17 microns, and the rate of hydrogen consumption measured 11 cc. per hr. The proton percentage was found to depend on the oscillator power and critically on the gas pressure. The magnetic field increased the proton percentage, but in an unpredictable manner. It was also found that the focusing lens in front of the probe canal exerted an extracting action on the ions in the discharge; influencing very strongly the total ion beam current collected. The general performance of the ion source was found to be satisfactory. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The phenomenon of anodization in the plasma of a dc low pressure oxygen glow discharge is investigated, both from the viewpoint of the mechanisms involved and for potential applications. Aspects studied include the effect of discharge conditions on anodization rate, the significance of negative oxygen ions in the plasma, the ionic current field strength relation in the oxide, and the anodization of metal films on silicon for MIS devices. It was found that the process does not utilize gaseous negative ions from the neutral plasma, and that species transport through the oxide is by high field ionic conduction. The variation of anodization rate with discharge conditions was attributed principally to a dependence of the oxide field strength on the electron energy distribution and density in the plasma. Double oxide layer MIS structures were fabricated, and charge storage effects were investigated. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate