Summaries - Research
Back Measurement of Ship-Induced Optical Turbulence and Modeling its Impact on High Energy Laser Beam Propagation
|Division||Graduate School of Engineering & Applied Science|
Cohn, Keith R.
Blau, Joseph A.
|Sponsor||Office of Naval Research (Navy)|
|Summary||Heat convection from the ship deck and air flow around the superstructure can produce optical turbulence above the deck, which could affect high energy laser (HEL) beam propagation. Previous research by Drs. Joseph Blau and Keith Cohn, in collaboration with SPAWAR and NSWC Dahlgren, has shown that ship-induced turbulence can be significantly higher than the levels of turbulence over open ocean. Having these effects near the laser source enhances the integrated effect over the beam path, potentially leading to significantly less power delivered to the target. However, no concerted effort has been made to measure this ship-induced turbulence on deployed warships. It is this deficiency that this research will address. We will measure turbulence at multiple locations on various classes of ships, including DDGs, LPDs, and LCSs. We will collect data in port as well as underway in a variety of weather conditions. We will estimate the impact of the measured turbulence values using HEL propagation models developed at NPS and elsewhere. We will correlate the turbulence measurements with other simultaneously measured atmospheric parameters. This correlation analysis may involve artificial intelligence (i.e., machine learning algorithms). The goal of this analysis will be to provide guidance on instrumentation for a deployed weapon system to estimate the level of optical turbulence based upon deck-air temperature difference, wind speed and direction, etc. We will also study methods of mitigating ship-induced turbulence, including the optimal placement of the beam director and the use of adaptive optics. During these underway campaigns, we will also use sensors to measure aerosol concentrations and to obtain turbulence profiles along the beam path. Data from these sensors will be fed into HEL propagation models to predict irradiance on a target, and to estimate the amount of prime power or energy storage required to successfully neutralize a given target. NPS naval officer students will participate in this research, contributing to their education on directed energy weapons. Deliverables from this project will include student theses, monthly written reports, and presentations to the sponsor|
|Publications||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|
|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|