Pulsed chemical laser with variable pulse-length electron-beam initiation and magnetic confinement

The effect of initiator pulse duration on the performance of a pulsed chain reaction chemical laser is investigated using a two-level vibrational model. Analytic results are presented for a saturated laser in the limits of weak and strong initiation. The initiator is assumed to provide a uniform (e.g., electron beam), parabolic (e.g., flash-lamp), or power-law variation ofF-atom production rate F B with time. Laser performance is presented as a function of t Bit., where t Band t e are initiator and laser pulse times, respectively. In the weak initiation regime, an increase of t a Ite from zero to one results in a decrement in laser output energy of 20 and 33j% for a flash-lamp and electron-beam initiator, respectively. In the strong initiation regime, an increase of t Bite from zero to one results in an energy decrement of only 5 and 10% for a flash-lamp and electron-beam initiator, respectively. In each case, the laser-pulse time te is increased by a factor of 2 as tB Ite

The effect of initiator duration on pulsed chemical-laser performance

Mirels

1982

Further improvement of the high-efficiency, high-energy hydrogen-fluoride chain chemical lasers initiated by an intense electron beam

Kannari

Ashidate

Obara

1988

In order to further improve the output performances, the operational characteristics of the hydrogen fluoride (HF) chain chemical lasers initiated by an intense electron beam were theoretically analyzed with a new computer code including ionic reactions. Both theoretical HF laser output energy and pulsewidth were in good agreement with the experiment. Furthermore, we made an optimization of the laser gas mixtures and the electron-beam-current density in order to obtain a high efficiency within the limit of our experimental conditions. In consequence of the experiment based on the theoretical results, a maximum output energy of 5.0 kJ (268 J/ℓ ) was obtained from the low total pressure mixture (282 Torr) of F2/H2/SF6/O2=139/58/45/42 (Torr) with a high electrical efficiency of 284% and a chemical efficiency of 20.3%. The corresponding total efficiency reached 18.9%. Moreover, aiming at the achievement of the high chemical efficiency, a maximum chemical efficiency of 29.6% was attained with a 317-Torr mixture of F2/H2/SF6/O2=167/30/70/50 (Torr). The maximum output energy was 4.9 kJ (259 J/ℓ ), corresponding to a high total efficiency of 26.4% and an electrical efficiency of 246%.

Ion kinetics study of a high-efficiency, high-energy hydrogen fluoride chain chemical laser initiated by an intense electron beam

Ashidate

Obara

1989

The operational characteristics of intense electron-beam (e-beam) initiated hydrogen fluoride (HF) chain chemical lasers were theoretically analyzed with a new computer code including both neutral and ionic reactions. The gas mixture used is F2/H2/SF6/O2. Both theoretical HF laser output energy and pulse width were in good agreement with those of the experiment. Using this code, we calculated the performance characteristics as a function of e-beam current pulse width, initial total gas pressure, H2 partial pressure, O2 partial pressure, and gas temperature. In order to optimize the total gas pressure, we introduced a new parameter which shows the effect of the pressure rise by the exothermic chemical reactions. The optimum total gas pressure of 850 Torr was predicted in our system. Moreover, by lowering the initial gas temperature from 300 to 220 K both the output energy and the chemical efficiency were improved.