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This Defense Intelligence Reference Document, DIA-08-1004-005, is dated 6 April 2010. The Defense Intelligence Agency's Defense Warning Office prepared it under the Advanced Aerospace Weapon System Applications program. It reviews proposed laboratory generators and detectors for high-frequency gravitational waves. It favors a piezoelectric approach for proof-of-concept tests, IR-excited molecules for an operational transmitter and the Li-Baker detector as the receiver. It estimates about 1.9 million bits per second over 7,000 km through the Earth and discusses timing standards and interplanetary navigation uses.
From the source: Release of 2026-09-18 Incident: 4/6/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD examines whether high-frequency gravitational waves could serve as a communications medium while avoiding the attenuation that limits radio-frequency systems. The report surveys proposed transmitter and detector concepts, argues that gravitational-wave communications could support secure point-to-point links, timing standards, and interplanetary navigation, and gives particular attention to laboratory generator concepts and the Li-Baker detector as possible building blocks for such a system. The document makes clear, however, that the entire concept depends on capabilities that had not been demonstrated in practice, including laboratory-scale generation and reliable detection of usable high-frequency gravitational-wave signals. It is an exploratory systems-oriented review built around a future communications concept.
UNCLASSIFIED//EOR OEEICI0L Llili QI\IL¥ The figure of merit for a HFGW generator is given explicitly by Baker, Woods and Li (2006). This Figure of merit can be extended by considering other effects since in the laboratory the force change could not even approach those of the celestial sources. It would seem that the magnitude of any laboratory generated GWs could be best increased (1) by utilizing electromagnetic forces rather than gravitational, (2) by increasing the distance between the gravitational radiators, (3) by increasing the GW frequency (that is, reducing ~t) and especially ( 4) by developing a large number of in phase system elements. This last effect enters as the square of the number of elements, N , as proved using General Relativity analyses by Dehnen and Romero Borja's analyses (Romero and Dehnen, 1981; Dehnen and Romero, 2003). Such N2 dependence also may be the key to successful laboratory generation of GWs, especially HFGWs. In that regard, recent proposal by Woods (Woods and Baker, 2009; Black and Baker, 2009)) propose the use of infrared-energized atomic nuclei, electrons and or molecules, which have a very large N, contained in a stack of N waveguide rings (Patents Pending). The distance between GW radiators may be proportional to the GW wavelength in that it may have a limit that is less than or equal to a GW wavelength. The wavelength is inversely proportional to the GW frequency. Thus given some value for the proportional constant, say unity or the distance between radiators equal to one GW wavelength, the GW frequency cancels out. As already noted it is important to take advantage of square of the number of in phase elements for useful laboratory HFGW generation. If the elements are sliced in one dimension (the dimension along the axis of HFGW generation) in order to increase the number of elements, then the change in force per element will be inversely proportional to the number of elements. For example, if the elements are sliced into one hundred separate pieces, then each piece will have one hundredth of the force of the unsliced element. Essentially, f = ma and it is assumed that the acceleration of the element was the same after the split as before. This result also follows Equation (8), page 17 in Baker, Stephenson and Li (2008b) and if there were 100 splits of an FBAR, then the power to an individual slice, P and its mass, m would be both one hundredth of their un-split value and the square root of their product would again be one hundredth. The frequency of the spl it elements may be a higher value -- but the attendant increase in GW power proportional to the square of the higher frequency and the decrease in power due to a smaller distance between tracks (assuming that the distance between tracks is one GW wavelength, which would be smaller) would cancel and there would be no net effect on HFGW amplitude. It is concluded, therefore, that in this particular special situation the amplitude of the generated HFGWs is proportional to the number of in-phase elements, N (not the square). In any event a large number of elements for a given HFGW-generator length can be best realized by reducing the size of the individual elements to submicroscopic size (as discussed in U. S. Patent Number 6,784,591). In the case of HFGW generation for communications applications, it is important to relate the amplitude of a GW, A, with the power, P, or more exactly with the GW flux, FGw, in wm-2 . For a viable communications link, the HFGW amplitude, A, must be large enough to be detected at the HFGW receiver. From Appendix B of Baker, Woods and Li (2006), A= 1.28x10-18 ( FGw/VGw) 112 m/m (2) where A has the dimensionless value of spacetime strain or m/m and VGw is the GW frequency s-1 . Following the proceeding numerical example we will concentrate the HFGW on a diffraction -limited area of 4x 10-3 m 2 or 0.004 m 2 for a HFGW flux of UNCLASSIFIED/ /FOR OEEICIJ.b HSI!! Dflti 5
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 57 pages are in the text index: search them above, or from the library's search.