Two sets of experiments indicate a renewal of interest in South Africa in the topic of laser propulsion. Both sets were conducted under the auspices of the new National Laser Center. In the first set, a 1 kW, CO2 laser (1 kHz, 1 J, 100 ns) was used to propel small (ca 1 gram) targets through a vertical tube-launcher and the momentum-coupling coefficient for a variety of conditions was estimated. The somewhat disappointing results were accounted for in terms of the poor beam quality from a single oscillator and premature break-down of the exhaust vapor in the tube. These experiments were conducted with one module of the now dismantled 'MLIS' uranium isotope separation system. The second set of experiments being conducted in Durban with a small but more energetic 'marking' laser (CO2 20 Hz., 4 J, 100 ns). The chief purpose of this, was to better understand the discrepancies between the recent vertical propulsion experiment at Pelindaba and earlier propulsion attempts with the original MLIS chain. Preliminary pendulum experiments were carried out. Burning targets exhibited enhanced coupling for single pulses.
Hybrid laser experiments have been conducted in a variety of high power/energy laser experiments: beat wave electron accelerators, rainbow and ignitor fusion, particle acceleration and double pulse laser propulsion schemes. Following our determination that the momentum coupling coefficient for burning targets is much higher than for cold targets, we propose using solar energy from a vast thin foil mirror, laid on a pre-prepared surface, to boost the satellite during its atmospheric trajectory. Solar power propels a lighter than air craft during the first part of the ascent and enhances the coupling to the pulse laser during the second. We present preliminary pendulum coupling results for burning targets and describe a solar and laser hybrid experiment.
Ashokabose Moorgawa, Max Michaelis, R. Diab, J. Anderson, M. Kuppen, A. Prause, Edric McKenzie, Jacques Porteneuve, Jean Leveau, Hassan Bencherif, B. Morel, P. Cunningham
A brief description and use of two LIDAR (Acronym for LIght Detection And Ranging) systems in the measurements of atmospheric aerosols and vertical temperature profiles above Durban are presented. Early local aerosol profiles for low medium and high altitudes from the old LIDAR are shown. With the recent installation of the new LIDAR, vertical temperature measurements in the troposphere and stratosphere are made possible. A first validation of the new LIDAR has been carried out showing atmospheric wave activity above the Southern African continent for the first time. It is envisaged in the future to correlate the results obtained with the new LIDAR, especially for the low altitude, with those of the old LIDAR. Plans are also going ahead to implement an additional channel on the new LIDAR which will measure ozone concentration in the troposphere.
The words of this title may at first seem incompatible. We review a range of experiments where dynamic structures have been created. We show that it is possible to construct gas and plasma shapes using colliding shocks cigars and cylinders, curved waveguides, and even waveguides with rectangular cross sections. The colliding plasma lens/isolator lead to the colliding shock lens. We now suggest that colliding shock waveguides could find application in laser acceleration and soft X ray schemes. Colliding shock waveguides can be as long as necessary unlike gas jets.
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