A low diffraction beam technique for scanning in the shallow ocean
The Localized Wave pulse project has created the concept of highly localized, pulsed wave energy. We have confirmed, and developed the technique in a series of experimental and numerical tests. This technique generates radiation, mechanical or electromagnetic, from an array. LW generation sends a broad frequency bandwidth pulse of energy along the array axis. The pulse has no sidelobes and maintains the frequency bandwidth and pulse amplitude better than any other method proposed to date. Confirmation of the theory by acoustic experiments show that the effect is real, and that the advantages of the technique can be realized in a laboratory environment. Numerical studies have shown that this effect is extendible to the microwave (vector field) and elastodynamic (tensor field) regimes as well as the stratified ocean environment. The main features of the LW beam are (1) the pulses are broad bandwidth and maintain that bandwidth over their entire working range; (2) the beam generates no side lobes; (3) the LW effect is accomplished in the linear regime, so that small errors in beam generation result in a less effective beam not the loss of the effect; and (4) the beam can be generated using present technology in the acoustic realm. The LW beam has a wide range of applications. As an active source, it offers a unique method of variable beam forming from spatially wide to the narrowest possible beam. Its uses include oceanographic sound velocity profile estimation and attenuation measurements. Since the pulse characteristics are changeable through the source signal parameters, it also offers the possibility of adaptive beam forming in real time. Passively, the LW array can use a wide spatial width listening pattern until something of interest occurs. Instantaneously, the listening pattern could be changed to a very narrow, steerable beam with a broad bandwidth. These uses also apply in the electromagnetic realm.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 67717
- Report Number(s):
- UCRL-JC-119287; CONF-9406241-2; ON: DE95011742; TRN: 95:004586
- Resource Relation:
- Conference: Inversion methods in ocean and seismic acoustics conference, La Spezia (Italy), 27 Jun 1994; Other Information: PBD: 1 Dec 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Localized wave transport of pulsed beam energy
STUDY OF ACTIVATION OF COAL CHAR