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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//&Olil OiiiilCI0L Llili QPIL¥ (2.8x1Q·13 )/(4x1Q· 3 ) = 7x10· 11 wm · 2 . Thus A= 2x1Q·33 It is an extremely small. HFGW amplitude, but possibly a detectable signal. 2.1.2 Alternative Approaches There are several alternative approaches to the laboratory generation of HFGWs developed over the past 45 years as discussed in the preceding Section 2.1.1. They can be categorized as EM -cavity generated, nuclear-energy generated, superconductor generated, laser-impact generated and energized microscopic & submicroscopic-particle generated HFGWs. Of these categories the last category appears to be the most promising for early deployment in HFGW communications systems. Furthermore, one embodiment of that category: the Magnetron-energized FBARs generator, utilizing off the-shelf equipment, would seem the most useful for proof-of-concept tests. For a practical, operational commun ications system HFGW generator (transmitter) the strong dependence of HFGW generator's power on the number of radiating elements, N, recommends a system utilizing molecular elements as suggested by Braginsky and Rudenko (1978) or using Infrared (IR)-energized pentane molecules in a stack of circular waveguides as proposed by Woods and Baker (2009). The Magnetron-energized FBARs and the IR-energized pentane will be considered in the next-following sections. 2.1 .3 Piezoelectric Approach Let us consider the l.8x 108 cell-phone film bulk acoustic resonators or FBARs, 10,000 Microwave-Magnetron, proof-of-concept laboratory HFGW generator. Assuming a 10 μm distance or margin between the 100 μm square conventional FBARs, the overall length of the laboratory generator will be 110 x (10·6 m) x (l.8x 10 8 elements) = 19.8 km. It will have a total HFGW power of 0.066 W and for a distance out from the last in-line, in phase FBAR element of one HFGW wavelength (6 .1 cm) it will have a flux of 3.53 wm·2 , yielding a HFGW amplitude there of A= 4.9x 10-28 m/m. By the way, the inline set of FBAR elements also produces a more needlelike radiation pattern of HFGWs so that the flux and resulting A may even be larger. Although the frequencies may be different analyses (2003), one can extrapolate approximately from the results of Dehnen and Romero-Borja's analyses in which the ang le of the needle-like radiation pattern is inversely proportional to the square root of the product of the distance between the radiators (the width between FBAR bands or tracks) and N. The distance for the system discussed here is 6.1 cm and for Dehne n's system 0.00001 m, for a factor of 6,100 and N differs by (1.8x 108)/(5x 107 ) = 3.6 for a product of 2.2x 104 and the inverse of the square root is 6.7xl0·3 . Using the result from Dehnen's paper (Equation (4.51), page 12) of a needle half angle of 1. 7 degrees we would extrapolate to 0.0115 degrees or very approximately 2x10·4 radians. Since there is no longer the constraint to the use of rudimentary off-the-shelf components as there was for the proof-of-concept apparatus, the specially designed submicroscopic elements can be manipulated. First, they will be staggered into two bands or tracks of 100 rows each or 110 x 100 μm = 1.1 cm wide bands of FBARs a wavelength or 6.1 cm apart. The rows will be staggered by displacing adjacent rows in the bands by 1.1 μm. Thus the overall length will be reduced to 198 m. Second, the 100 μm length of each FBAR element can be sl iced, along the direction of travel of the HFGW build up, into one-hundred 1 μm wide slices (exhibiting 0.1 μm margins). The staggered row displacements are now reduced to 11 nm. The overall length will be reduced to about 198 cm. Concentrating the 10 MW power to each of these 1.1 cm wide bands may prove to be difficult. Thus, as an example, the continuous-wave Magnetrons will be replaced by a pulsed microwave source having UNCLASSIFIED/ /FOR OiiiilCl.t.k HSI!! eflti 6
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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.