| Resonant Laser Manipulation of an Atomic Beam |
01 Jul 2010 |
7 pages |
| Authors:
T C Lilly; A D Ketsdever; S F Gimelshein; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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 | Theories for laser-atom interactions have been under development since the advent of laser technology. The theories have yet to be adequately integrated into kinetic flow solvers. Realizing this integration would greatly enhance the scaling of laser-species interactions beyond the realm of ultra-cold atomic physics. A representative numerical investigation was conducted using a custom collisionless gas particle trajectory code, demonstrating this goal in the present study. The investigation covered neutral atomic ... |
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| Impact of Separation Distance on Multi-Vane Radiometer Configurations |
01 Jul 2010 |
7 pages |
| Authors:
B M Cornella; A D Ketsdever; N E Gimelshein; S F Gimelshein; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The radiometric force produced by a linear array of three radiometer vanes has been assessed numerically using an argon carrier gas and experimentally using air. The separation distance between the three vanes of the array was varied between 0 and 120 percent based on the height of an individual radiometer vane of 40mm. Qualitative agreement between the numerical and experimental results is shown as a function of operating Knudsen number, ... |
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| Experimental and Computational Investigation of a RF Plasma Micro-Thruster (Preprint) |
08 Jul 2008 |
9 pages |
| Authors:
J D Olliges; A D Ketsdever; W B Stein; A A Alexeenko; I Hrbud; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
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| A prototype RF plasma micro-thruster has been investigated numerically and experimentally. The experimental results were obtained on a thrust stand capable of micro-Newton resolution. Thrust and mass flow (hence specific impulse) were measured for an argon propellant at mass flows ranging from 0.4 to 5.5 mg/sec. An increase to the cold gas thrust of up to 20% was observed for a discharge frequency of 100 MHz and an input power ... |
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| Energy Deposition into a Collisional Gas from Optical Lattices Formed in an Optical Cavity (PREPRINT) |
02 Jul 2008 |
8 pages |
| Authors:
T C Lilly; S F Gimelshein; A D Ketsdever; M N Shneider; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The Direct Simulation Monte Carlo (DSMC) method was used to investigate the interaction between argon, nitrogen, and methane test gases and ten successive pulsed optical lattices. The one-dimensional lattices were formed by two 100 ps, 393 mJ, 532 nm, laser pulses and were assumed to be far from any electronic resonance. The sequential interaction represents multiple reflections within an optical cavity or the emission of high repetition rate pulsed lasers. ... |
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| Effect of Chamber Wall Proximity on Radiometer Force Production (Preprint) |
02 Jul 2008 |
8 pages |
| Authors:
N P Selden; N E Gimelshein; S F Gimelshein; A D Ketsdever; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The impact of chamber wall location on a radiometric device has been studied experimentally and numerically in chambers from 0.2m to 1.8m in diameter with background pressure ranging from 0.006 to 1Pa. The range of pressures investigated is broad enough to observe the impact of the chamber walls on a given radiometer configuration in both the free molecule and transitional regimes. The contribution of the chamber walls to both the ... |
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| Development of a Specific Impulse Balance for a Pulsed Capillary Discharge (Preprint) |
13 Jun 2008 |
8 pages |
| Authors:
A D Ketsdever; T C Lilly; A P Pancotti; M Young; J A Duncan; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| A capillary discharge based pulsed plasma thruster is currently under development at the Air Force Research Laboratory. A torsion thrust stand has been developed to simultaneously measure the shot by shot total impulse and propellant mass loss of the thruster, yielding a per shot specific impulse. Competing design considerations affecting the performance of the thrust stand has lead to an optimized diagnostic tool capable of measuring total impulses up to ... |
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| Experimental and Computational Study of Area and Perimeter Contributions to Radiometer Forces (Preprint) |
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7 pages |
| Authors:
N P Selden; E P Muntz; S F Gimelshein; A Alexeenko; A D Ketsdever; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The relative contribution to the radiometric force of the area and perimeter of the vane is studied experimentally and numerically. Experimentally, a circle, a low-aspect rectangle, and a high-aspect rectangle were all tested on a thrust measurement stand with nano-Newton resolution placed in a stagnant gas. The computational results were obtained through 2-D simulations using the direct simulation Monte Carlo method, as well as a discrete ordinate solution of the ... |
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