Research Summaries

Back Measurement of Ship-Induced Optical Turbulence and Modeling its Impact on High Energy Laser Beam Propagation

Fiscal Year 2019
Division Graduate School of Engineering & Applied Science
Department Physics
Investigator(s) Barnes, Patrick W.
Cowart, John K.
Haacke, Erin
Sponsor Space & Naval Warfare Systems Center-Pacific (Navy)
Summary The proposed research investigates ship-induced optical turbulence and its effects on the beam propagation of a laser weapon placed on a warship. Heat convection and air flow above the ship deck can produce optical turbulence, resulting in random variations in the index of refraction. This can lead to beam degradation and wander, limiting the range and effectiveness of a laser weapon system. Having these effects near the source of the laser increases the amount of degradation that would happen over the beam path, potentially resulting in much less power delivered to the target area.
A recent experiment conducted onboard the USS SPRUANCE by Profs. Blau and Cohn and LT Jacob Busby, in collaboration with Dr. Steve Hammel of SPAWAR, showed that ship-induced turbulence above the deck can be significantly higher than the levels of turbulence over open ocean. Over the course of this experiment, many gigabytes of data were obtained from multiple sensors. Further analysis of the data is needed, including comparisons and correlation studies of the data from various sensors. Also, there is an urgent need for follow-on studies of this effect on other platforms in a variety of operational conditions.
The focus of this research is to (1) conduct further analysis of the results of the previous experiment, including an estimate of the impact the measured turbulence would have on a directed energy weapon; (2) compare various sensors and methods for quantifying turbulence; (3) take additional measurements on another type of ship, such as a San Antonio-class amphibious transport dock; and (4) study methods for mitigating ship-induced turbulence.
This research could provide guidance toward a model of ship-induced turbulence that, once integrated into the fire-control system, would allow watch standers on the vessel to be able to make real-time predictions of beam degradation and provide the warfighter with more accurate range and dwell time calculations. This would allow them to determine the effectiveness of the laser weapon and how best to employ it within the battlespace.
Keywords
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Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal