Organization:
Physics (PH)

Description

The mission of the Physics Department is to provide defense-relevant, advanced education and research programs to meet Naval unique needs, and increase the warfighting effectiveness of the U.S. Naval Forces, DoD and allied armed forces.

Website of the organization

https://nps.edu/web/physics

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Publication Search Results

Now showing 1 - 10 of 48

Lompoc Valley Diffusion Experiment analysis - Mt. Iron comparison and two zone convective scaling model
(Monterey, California. Naval Postgraduate School, 1992-01) Skupniewicz, C.E.; Kamada, Ray; Drake, S.A.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Physics
LVDE(Lompoc Valley Diffusion Experiment) was conducted Aug 1989 to assess the potential risk of gaseous releases from the Hypergolic Stockpile and Storage Facility at Vandenberg AFB. Results of the LVDE are compared to the predictive equations of the Mt. Iron Diffusion Tests, conducted at Vandenberg in the 1960's. The Mt. Iron equation parameterizes diffusion with on-base meteorological tower input data. Regression techniques similar to those of Mt. Iron are used in this comparison, resulting in LVDE equations which use the same meteorological data as input. Instantaneous and time averaged centerline concentrations, in both flat and complex terrain are analyzed. For all cases LVDE concentrations are shown to decrease with range less rapidly than the Mt. Iron equation predicts. We suggest that this bias is due to gravitational and/or scavenging losses of the tracer material used in Mt. Iron. A 'two-zone' convective scaling equation is developed which diffuses the plume differently in cloud covered and clear sky portions of the domain. The method is shown to be superior to homogeneous convective scaling equations, and comparable to a statistical approach based on the plume measurements. While the method works for maximum concentration predictions, it fails for plume width and crosswind integrated concentration for X > 6
Free Electron Laser material damage studies
(Monterey, California. Naval Postgraduate School, 2000-11) McGinnis, Roger D.; Thomson, R. W.; Short, L. R.; Herbert, A.; Lampiris, D.; Christodoulou, A.; Colson, W. B.; Shinn, M. D.; Neil, G.; Benson, S.; Gubeli, J.; Evans, R.; Jordan, K.; Physics (PH); Thomas Jefferson National Accelerator Facility; Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Institute for Joint Warfare Analysis
Today's surface ships are faced with an increased vulnerability to anti-ship cruise missiles, due to a change from operating in open oceans to primarily operating in the world's littorals. One possible solution to counter this threat is the use of a high-energy laser to destroy the missiles in flight. The Free Electron Laser is possibly the best choice of lasers for a marine environment since its wavelength can be changed over a wide range allowing the operator to choose the best wavelength to transmit through the atmosphere. Material damage studies on various anti-ship cruise missile materials were carried out at Thomas Jefferson National Accelerator Facility (TJNAF) in Newport News, Virginia. Experimental procedures presented in this report allow a scaled down laser of a few hundred to a few thousand watts to evaluate the damage from a weapon size laser of the megawatt class. The EEL beam bombards the target with a steady stream of picosecond length pulses at rates of 18MHz or greater. No other experiments have previously been done to explore the effects of the EEL pulse on materials. This report contains the work of several theses conducted at the Naval Postgraduate School over the past two years, and has been a productive cooperation among NPS, TJNAF, NRL, and NSWD at Port Hueneme, to the benefit of the Department of Defense.
Cerenkov radiation in the neighborhood of the emission threshold
(Monterey, CA; Naval Postgraduate School, 1984) Buskirk, Fred R.; Neighbours, John R.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Dept. of Physics
Correction to attenuation treatment in the Monterey-Miami Parabolic Equation Model
(Monterey, CA; Naval Postgraduate School, 2007) Smith, Kevin B.; Wolfson, Michael A.; van Leijen, A. Vincent; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.)
The purpose of this report is to notify those in the community who have used, or are using, the Monterey-Miami Parabolic Equation (MMPE) Model of an error in previous implementations that affects the computation of volume loss. The error has been corrected and an updated version is now available. Thorough analysis of the results are provided here, including comparison with exact modal attenuation factors for bottom loss parameters, which indicate the model is now performing properly.
Cerenkov and sub-Cerenkov radiation from a charged particle beam
(Monterey, CA; Naval Postgraduate School, 1987) Neighbours, John R.; Buskirk, Fred R.; Maruyama, Xavier K.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Physics
As a consequence of the relaxation of the phasing conditions between the moving charge and radiated wave for finite beam path lengths, the Cerenkov peak is broadened and the threshold energy is developed which is applicable to charged beams consisting of single point charge or charge bunch of finite size, as well as beams consisting of periodically repeated bunches
A perturbation theory for light diffraction from a bigrating with multiple surface-polariton excitation
(Monterey, CA; Naval Postgraduate School, 1986-12) Glass, Nathaniel E.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Dept. of Physics
A perturbation theory has recently been developed for treating the diffration of light, with surface polariton resonant excitation, from a bigrating surface. The theory is an approximation, to first order in the grating height, of an earlier theory based on the Rayleigh hypothesis. The perturbation theory holds for arbitrary polarization and for arbitrary plane of incidence with respect to the grating directions. It is, however, limited to treating only the possibility of two simultaneous resonant evanescent waves, whereas four are possible at normal incidence on a square grating, and three are possible on a rectangular grating. The present work generalizes the earlier work to allow for a four fold (or three fold) resonance. This extension also allows one now to determine the complex dispersion relation for surface-polaritons, for wavevectors at the intersection of two Brillouin zone boundary lines (not possible in the previous formulation). Keywords: Smith Purcell radiation; Bigrating; Grating; Surface plasmon; Polariton
Basic Research in Thermoacoustic Heat Transport
(Monterey, California. Naval Postgraduate School, 1996-06-11) Atchley, Anthony A.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Physics
This technical report details progress in basic research in thermoacoustic heat transport made during the period June 1, 1995 through May 30, 1996. Research efforts were primarily concentrated in three areas: 1) investigation of fundamental limitations to the performance of thermoacoustic devices; 2) design, construction, and demonstration of a proof-of-concept, shipboard, heat driven thermoacoustic cooler capable of cooling loads of 1 kW; 3) measurement of transient effects in thermoacoustic devices to provide data to test nonlinear, timedependent models of thermoacoustics. Accomplishments include 1) the design of a prototype toroidal prime mover; 2) preliminary measurements of the temperature evolution along a stack in a mechanically driven configuration; 3) preliminary measurements of transient effects in prime movers; 4) preliminary design of a new prime mover configuration; and 5) fabrication of a 1 kVV heat driven cooler. A publications, patents, presentations, and honors report is also included.
System for laser spot profile analysis
(Monterey, CA; Naval Postgraduate School, 1983-05) Crittenden, Eugene Casson; Milne, Edmund Alexander; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Dept. of Physics
Sea test development of laser altimeter
(Monterey, California. Naval Postgraduate School, 1991-01) Crittenden, Eugene Casson; Rodeback, George Wayne; Milne, Edmund Alexander; Cooper, Alfred William; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Physics
Low altitude (81 m.) narrow-beam laser reflectance measurements were made from the nearly ocean-like water surface under the Golden Gate bridge. This site allowed precise measurements not possible from flying platforms. For short wavelength water waves superimposed on swell, the signal amplitude probability distribution showed periods of zero return signal, even for vertical incidence, apparently due to tipping of the average water surface. The nonzero signals show an antilog-normal probability distribution, skewed toward higher signal than that provided by a normal (Gaussian) distribution. With incidence angle displaced from the vertical, the distribution shape is retained but with more frequent zero reflections. The decrease with angle of the average signal, including the zeroes, is well fitted with a Gram-Charlier distribution, as seen by earlier observers using photographic techniques which masked these details of the structure. For the simpler wave pattern due to a long sustained wind direction, the signal amplitude probability distribution is lognormal with no zero signal periods. For this case, the distribution shifts toward exponential at large angles from the vertical. For surface states intermediate between the above two extremes the distribution is often normal. The larger return signals resulting from the skew toward larger amplitudes from lognormal are more favorable for disposable laser altimeters than previously believed. Also for an altimeter which may be swinging from a parachute or balloon, the return at angles from the vertical remains high. The presence of occasional zero return signal does degrade the accuracy of altitude somewhat for a descending altimeter, but the signal available assures performance at larger altitudes than previously expected.
Emission threshold for Cerenkov radiation
(Monterey, CA; Naval Postgraduate School, 1985) Neighbours, John R.; Buskirk, Fred R.; Maruyama, Xavier K.; Physics (PH); Graduate School of Operational and Information Sciences (GSOIS); Naval Postgraduate School (U.S.); Physics