Laser propulsion experiments in South Africa

Abstract

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 ofthe new National Laser Center. In the first set, a 1 kW, C02 laser (1 kHz, 1 J, 1 00 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 ofthe now dismantled MLIS" uranium isotope separation system.The second set of experiments are being conducted in Durban with a smaller but more energetic "marking" laser. (C02, 20 Hz., 4 J, 100 ns). The chiefpurpose ofthis, 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.

Laser Propulsion Standardization Issues

“…Launches were investigated by many groups [12,13,14]. In launch experiments with a parabolic thruster coupling coefficients have been found to tend to be slightly higher than measured at an impulse pendulum [15].…”

On verification of micro-nanonewton range recoil momentum evaluation techniques at solid targets laser ablation

“…1, а), используются также акселерометры [17] или датчики линейных перемещений [18] (например, вихревых токов [19], емкостные, индукционные, электромеханические [20]). Применение последних в сочетании с плазменными устройствами в [21] Прямые траекторные измерения полета мишени или макета также могут быть использованы для определения оптико-механических характеристик лазерных систем генерации тяги [27][28][29][30]. Такой запуск может рассматриваться как частный случай импульсного маятника, однако получаемые результаты оказываются несколько больше, чем те, что регистрируются в аналогичных условиях с использованием маятника [27].…”