UNCLASSIFIED//FOR OFFICIAL UDE OML¥ Defense Intelligence Reference Document ^ ^ ^ ^ ^ ^ ^ ^ A cquisition Threat S upport 23 March 2010 :C OD: 1 Decem ber 2010 DIA-08-1003-013 The Role of Superconductors in Gravity Research UNCLASSI FIED//FOR OFFICIAL USE ONE! UNCLASSI FIED //FOR OFFICIAL USE OHLY The Role of Superconductors in Gravity Research Prepared by: Acquisition Support Division (DWO-3) Defense Warning Office Directorate for Analysis Defense Intelligence Agency Author: A A P Person 75 Administrative Note COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one in a series of advanced technology reports produced in FY 2009 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapon System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to|AAP Person 1 |, AAWSA Program Manager, Defense Intelligence Agency, ATTN: CLAR/DWO-3, Bldg 6000, Washington, DC 20340-5100. i UNCLASSIFIED //BOR OPHMAL USE ONLY UNCLASSI FIED/ / FOR OFFICIAL USE ONLY Contents Introduction.................................................................... ..............iii Gravity Waves............................................................................................. 1 Gravitoelectromagnetism............................................................. 1 Historical Timeline...................................................................................... 3 Conclusion...................................................................... 11 ii UNCLASSI FIED//FOR OFFICIAL USE ONLY UNCLASSI FIED/ / FOR OFFICIAL USE ON LT The Role of Superconductors in Gravity Research Introduction This paper is a historical survey of the role superconductors have played in the recent search for laboratory-scale manipulation of gravity. The invention of superconductors and, in particular, the recent development of high- temperature ceramic superconductors have provided the impetus for pursuing a connection between gravity, electromagnetism, and, in particular, magnetism and matter in the solid state. The discovery of yttrium-barium­ copper oxide (YBCO) YBaiCusO? ceramics able to superconduct at liquid nitrogen temperatures allowed many laboratories around the world to fabricate these superconductors in various experimentally useful sizes. True Meissner repulsion was obtained by cooling them using relatively cheap liquid nitrogen rather than liquid helium. For the theoretician, the possibility of considering the superconductor being a macroscopic quantum object as a reality rather than a fantasy suggested several avenues for developing theories connecting gravity and gravity-like forces to engineerable matter. For the experimentalist, extrapolations from these theories suggested there might actually be gravitational disturbances in the laboratory that would be amenable to measurement, assuming all necessary precautions were taken to exclude artifact. iii UNCLASSI FIED//FOR OFFICIAL USE ONL¥ UNCLASSIFIED//rOR OFFICIAL UOE ONLY Gravity Waves A distinction should be m ade between gravitational waves, the gravitational "force," and anom alous forces. C urrently, work on gravitational waves is divided into two m ore or less distinct realm s: low frequency (less than a few hundred Hz) and high frequency (greater than ~ several tens of kHz). The existence of gravitational waves of any frequency is a natural outcom e of Einstein's theory of general relativity (GR). The search for low-frequency gravitational waves currently utilizes large, heavy, and long m etal bars as detectors together with interferom eters, strain gauges, and accelerom eters in an attem pt to detect quadrupolar gravitational waves from cosm ological sources, such as binary stars. The general idea is that if a large m ass of precisely known dim ensions is effectively isolated from the surrounding environm ent (such as Earth) by m eans of special vibration and other isolators, the m asses will interact with the sm all-am plitude gravity waves em itted by large m asses in the cosm os and their lengths will change, but by extrem ely sm all am ounts. LIGO, LISA, VIRGO, DEC IGO (Japan), and C EGO (C hina) are som e of the acronym s given to these experim ents. They are prim arily attem pts to verify the existence of these waves to further solidify the understanding that GR gives us about the nature of space and m atter. Several researchers consider that high-frequency gravitational waves (HF GW ) will be produced in the laboratory under certain conditions in the near future (Reference 1). These researchers have a considerably m ore am bitious view of the future than the low-frequency gravitational wave researchers, including the use of HF GW for com m unications, telescopy, m icroscopy, and possibly propulsion. Som e consider that the production and detection of these waves will be m ediated, or at least assisted, by superconductors (References 2, 3). C urrent research on the link between HF GW and the m anipulation of gravity for propulsion is at present only theoretical. If gravitational waves can interact with and be converted into forces in laboratory-scale m atter, it is hoped that those forces would be m anifest not as gravitational forces per se, as these gravitational forces would be exceedingly sm all and difficult to unequivocally detect in the laboratory, but rather as electrom agnetic or ponderable nongravitational forces, thus m aking them m ore am enable to detection by electrom agnetic m eans. Gravitoelectromagnetism The gravitational "force" arises from the tendency of one body to accelerate toward another. (F orce is in quotation m arks here m erely for sim plicity and ease of use when com paring gravity with other forces, as m any other gravity-like forces can be easily confused in the laboratory with actual gravitational attraction.) The physical explanation for gravitational attraction has been elusive at best. Several notable attem pts at novel explanations have recently been published. Puthoff (Reference 4) developed an idea originally put forward by Sakharov (Reference 5) that posits gravity as a C asim ir-like attraction arising within the universal sea of fluctuating electrom agnetic interactions, som etim es called zero-point fluctuations. Alzofon (Reference 6) presented an engineering approach to interacting with gravity by m eans of altering nuclear entropy using a technique associated with electron param agnetic resonance called dynam ic nuclear orientation— that is, enhanced polarization of the m agnetic m om ents of nucleons by interaction with pulsed polarized electron spins. Hughes (Reference 7) analyzed the K opernicky C onjecture, which holds that gravity is nothing other than the slight difference between forces of coulom b attraction and repulsion. However, none of these researchers appealed to the special form of m atter constituting superconductors. 1 UNCLASSI FIED//TOR OFFICIAL UOE ONL¥ UNCLASSI FIED/ / FOR OFFICIAL USE ONLY The "attraction" of m odifying gravity— whether your own, your spacecraft's, or that of a nearby large m ass— for propulsive purposes lies in two general categories of effect: • The m odifying, neutralizing, or negating of the gravitational attraction of a nearby body, typically Earth. • The provision of propulsive force or im pulse to a spacecraft based on m anipulation of the sam e underlying physical phenom enon that form s the basis of gravity. The theoretical and experim ental attem pts outlined in this paper deal with both these possibilities. In experim ents designed to produce a gravity-like force or to interact directly with a local gravity field, the researcher has to be looking for extrem ely sm all deviations from a null result. Observations to date dem onstrate that interactions between gravity and electrom agnetic fields, given the field densities and strengths available to even the m ost well-equipped laboratory, are m any orders of m agnitude sm aller than those required to begin to see such forces. Braginski et al. (Reference 8) showed that ordinary m atter cannot be used to generate m easurable gravitational fields in the laboratory. The standard edict against such things as gravity shields can be sum m ed up by noting the absence of negative gravitational m ass, at least in this sector of the universe, resulting in the relative "gravitational perm ittivity/ perm eability" being unity in norm al m atter. Therefore, dem onstrating that a new force, whether gravitational or not, has been discovered in the laboratory will require an intense effort to provide proof. This im plies being able to distinguish between true gravity-like forces and gravity interactions and a host of prosaic effects m asquerading as these forces. A list of potential artifacts attendant on such experim ents can be found in Reference 9. General relativity introduces a m etric tensor theory of gravity, and while it does not explain the fundam ental physical basis of the gravitational attraction between two bodies, it does allow the prediction of a large range of interactions between bodies. Sim ilarly, Maxwell's vector equations do not explain the fundam ental basis for electrom agnetic interactions but do allow us to predict the outcom es of such interactions. It is possible to reform ulate the tensor form at of GR into a sim ple vector form at that is valid only for a subset of GR conditions, nam ely in the weak field approxim ation and for nonrelativistic velocities. Using perturbation theory, for exam ple, to com pute the equations of m otion in the sim plified GR equations results in term s that have direct analogs in Maxwell equations where electrical current flow is replaced by m ass flow, for exam ple. F orward (Reference 10, 11) was am ong the first to investigate this analog. One term is analogous to the Biot-Savart-like m agnetic field and is generally referred to as the "gravitom agnetic field" (and also som etim es as "gravitational fram e dragging" or the "Lense-Thirring Effect") and has the dim ensions of s’1. Another term is analogous to the electrostatic coulom b field and is referred to as the "gravitoelectric field." Essentially, the gravitom agnetic field produces a force between currents of flowing m atter, while the gravitoelectric field produces a force between m asses them selves (the N ewtonian gravitational field). Som etim es the term "gravitoelectrom agnetic field" is used to refer to both the gravitoelectric and gravitom agnetic fields. Gravity is thus com posed of a (N ewtonian) velocity-independent field and a (gravitom agnetic) velocity-dependent field analogous to the electric and m agnetic fields 2 UNCLASSI FIED/ / FOR OFFICIAL UDE ONLY UNCLASSIFIED//FOR OFFICIAL USE OHL*? in electrom agnetic theory. The sim plified GR/ Maxwell equations show that there is also a F araday-like law of induction that can generate N ewtonian gravitational fields from tim e-varying gravitom agnetic fields. Modern attem pts to confirm the existence of the gravitom agnetic field include highly accurate laser ranging of the Earth-Moon distance (Reference 12), as well as the launch of the Gravity Probe B satellite (Reference 13). Historical Timeline In order to aid future researchers, it is instructive to follow the general historical developm ent of the m odern search for a link between electrom agnetism , m atter, and gravity. This outline will include both theoretical and experim ental aspects, expanding and em phasizing experim ental issues where appropriate. Because of space lim itations, not all of the m any contributions to the field can be highlighted. The reader is encouraged to consult the source references cited in this paper to obtain a fuller appreciation of the am ount of effort that has been expended in this area of physics. Podkletnov and N iem inen (Reference 15) published what is considered the first possible evidence for an experim ental link between high-tem perature liquid nitrogen (LN 2) superconductor effects and gravity, allegedly in the form of a gravity shield. Many scientists since then have cast considerable doubt on their findings. N otwithstanding these severe criticism s, since the publication of this paper, m any other researchers have considered that the experim ental search for gravity-related forces could be taken out of the realm of pure speculation and onto the laboratory bench. Podkletnov's apparent experim ental success has in turn prom pted som e theoreticians to consider fresh approaches to investigating superconductors as a special form of condensed m atter capable of m odifying and/ or producing such forces. It would be a breakthrough of the first order to discover a repeatable, laboratory-scale, heretofore hidden connection between gravity, special form s of m atter that can be created in the laboratory, and electrom agnetism that would possibly unlock the door to new transportation system s, new energy sources, and a host of other earthly benefits, not to m ention professional accolades and untold wealth for the technology developers. However, the rush to be the first to successfully find a repeatable and verifiable link between superconductors and gravity has produced m any casualties. Theoreticians have m ade assum ptions to force their theories to explain the putative experim ental results. Most experim ents have been literally thrown together with little thought paid to the m yriad traps and pitfalls that litter the m inefield of experim ental physics in this uncharted territory. This is prim arily due to the expectation that the sought-after forces will be extrem ely tiny and hard to distinguish from prosaic influences. The m ost prom inent, albeit controversial theoretical work on creating laboratory- detectable gravitom agnetic fields via high-tem perature superconductors was initiated by Li and Torr (Reference 16-18). Their work expanded on earlier work by DeW itt (Reference 19) and Ross (Reference 20), who considered m odifications to the London equations, which relate supercurrent (that is, C ooper pair) flow to electric and m agnetic fields in and around a superconductor, to include gravitom agnetic fields. Dewitt showed that a tim e-varying gravitom agnetic field m ust arise owing to the presence of m agnetic flux quantization in superconductors. Dewitt's work was expanded on by Ross, who 3 UNCLASSI FIED/ /MH OFFICIAL USE ONLY UNCLASSI FIED/ / FOR OFFICIAL USE ONLY produced a m odified set of London equations. These papers laid the theoretical foundations for the later work of Li, Torr, and Tajm ar, for exam ple. In the late 1980s while at the University of Alabam a, Douglas Torr was exam ining neglected areas of physics, including aether theories and experim ents, as well as gravitational wave antennas, the subject of a paper awarded the Gravity Research F oundation's "F irst Award" in 1989. In 1991, Torr and N ing Li published a paper on the effects of a gravitom agnetic field on superconducting m atter (Reference 16). Ordinarily, all m agnetic fields are excluded from the interior of a superconductor because of Meissner expulsion. However, by solving the coupled Maxwell, GR, and London equations for the internal m agnetic and gravitom agnetic fields of superconductors exposed to external gravitom agnetic and m agnetic fields, they predicted a sm all residual internal m agnetic field. This in turn produces an internal gravitom agnetic field. The fields are related to one another by the C ooper pair m ass-to-charge ratio. The gravitom agnetic field penetration depth is larger than the norm al m agnetic field depth. A year later the sam e authors presented papers at a m eeting of the Am erican Physical Society (Reference 17). Buoyed by the apparent success of their previous analyses, part of the title of one presentation was "A Theoretical Basis for a Principle of Electrically Induced Gravitation." In this paper, they used coupled Ginzburg-Landau equations to calculate the relative strengths of the electric and gravitational fields in superconductors in the presence of m agnetic and gravitom agnetic fields. They concluded that under certain circum stances, a secondary gravitational field could be induced inside a superconductor and "provide a basis for the electrical generation of gravitational fields in the laboratory." Then cam e the bom bshell. A Russian m aterials scientist on staff at the Institute of Materials Science at the Tam pere University of Technology in F inland published a paper in 1992 on an apparent gravity shielding experim ent using a spinning superconductor disk (Reference 15). In the m id-1980s, the lead author, Evgueny E. Podkletnov, had published several papers on ceram ics while at the Institute for High Tem peratures in Moscow. He later m oved to F inland, where he com pleted his doctorate under then- Director of the Institute of Materials Science Pentti K ettunen. Podkletnov's thesis was on preparation of pure YBC O whiskers by m agnetron sputtering, and he was producing this m aterial for powder-in-tube high-tem perature superconducting wire for a local business concern. According to K ettunen (Reference 21), the spinning disk experim ent was not actually perform ed at the institute but rather was conducted by Podkletnov and others "after hours." K ettunen also confided that although he was aware of the existence of the gravity shielding experim ent through "so m any others" telling him about it, he never witnessed it him self. He did confirm the story Podkletnov later told about discovering the shielding effect by watching the sm oke from a coworker's pipe float up exactly in the "shadow" of the spinning disk. The disk was apparently m ade in Russia for sputtering purposes and brought to F inland. The coauthor of the gravity shielding experim ent, Risto N iem inen (this Risto N iem inen is em phatically not the m ore fam ous professor of com putational physics currently at Helsinki University of Technology), was a technician working at the Institute of Materials Science during Podkletnov's tim e there. He was not involved in Podkletnov's experim ents but noted (Reference 22) that they were likely conducted at either the Tam pere Institute of Technology's Departm ent of Electrical Engineering or the Institute of Physics. To this day, he is still not sure why he was asked to coauthor the paper, 4 UNCLASSI FIED/ /fOR OFFICIAL UGE ONLY UNCLASSI FIED/ / FOR OFFICIAL USE ONLY except possibly for his proofreading skills. Strangely, the only persons who contacted Podkletnov in the m id-1990s about the paper were the Italian theoretical physicist G. Modanese and this author. Podkletnov claim ed he had never heard of the work of Li and Torr prior to publishing the paper. According to the 1992 paper, the essence of his experim ent was the high-speed rotation of a relatively large (14.5-cm diam eter x 6-m m thick) YBC O sintered ceram ic superconducting disk in the vapors of liquid helium (LHe). The disk was levitated by Meissner repulsion over a large support electrom agnet im m ersed in LHe that was powered by a variable-frequency supply from 50 Hz to 106 Hz. At the diam etrical periphery of the disk were positioned two additional but sm aller electrom agnets also powered by variable frequency supplies. These two "rotational" electrom agnets were used to spin the disk in som e unspecified m anner. A sm all nonconducting, nonm agnetic test m ass was suspended from an analytical balance about 15 m m from the top of the disk. Subsequent inform ation from Podkletnov indicated that to obtain the m axim um stable test sam ple weight loss of about 0.3 percent, the optim um conditions required operation of these two electrom agnets at frequencies of 105 Hz and disk rotational speeds of several thousand rpm . Apart from the difficulty believing, on purely theoretical grounds, that such an enorm ous weight loss was possible, there was considerable doubt about the validity of the observations based on experim ental issues. Am ong m any other concerns, a few com m ents regarding the cryostat are in order. The only inform ation on the physical configuration of the experim ent is given in the sketch provided in Reference 15. Referring to that figure, it is difficult to believe the only thing separating the vapors of LHe in the cryostat from the laboratory atm osphere was a thin plastic film . Ordinarily, so m uch water vapor and other gases would have condensed on the outer surface of the film as to render it com pletely opaque, thus m aking the observation of the disk extrem ely unlikely. If the cryostat was actually designed roughly per the sketch in the article, the LHe would be boiling so vigorously that it would rupture any film unless adequate He gas escape was provided. As pointed out by dePodesta (Reference 23), therm al currents and buoyancy changes above such a cryostat would be so severe as to render the determ ination of the weight of a test m ass suspended only 1.5 cm above the disk (and therefore only a few m m above a separating film covered with ice) virtually im possible. This was an entirely unsatisfactory cryogenic design for the purpose. Im portant issues such as how the disk was balanced, how it was prevented from rupturing at high speeds, how m uch power was used to operate the coils, and what m eans were em ployed to prevent the balance from being affected by the m agnetic fields from the coils were not addressed in the article. N evertheless, the article caused experim entalists around the world to try to duplicate the essence of the experim ent, generally in an overly sim plified m anner. All started out using the less costly LN 2 approach with either fixed or rotating perm anent m agnets and sm all (~ 2- to 3-cm diam eter) disks purchased com m ercially. Several researchers, including Gonnelli at Turin Politecnico (Reference 24), W oods at the University of Sheffield (Reference 25), and this author witnessed very slight apparent weight changes while the disk was passing through its critical tem perature, Tc. However, in m ost cases, the effect was so close to the noise that further experim entation was not considered. At a private unpublished m eeting (see below) hosted by Professor R. Gonnelli at the Turin Politecnico in April 1999, however, Podkletnov m ade it clear that unless the exact disk form ulation was followed, high-frequency m agnetic fields were em ployed (not 5 UNCLASSI FIED/ / FOR OFFICIAL USE ONLY UNCLASSIFIED//FOR OFFICIAL UOC ONLY perm anent m agnets), and a larger disk was spun at lower tem peratures, the shielding effect would be extrem ely sm all. The experim ent has rem ained controversial since its publication. Very few scientists put any stock into it at all. Most dam ning to Podkletnov's case was the com plete lack of any supporting evidence that the experim ent had ever actually taken place. As the Podkletnov article began to slowly circulate, Li and Torr published another article (Reference 18) expanding on their earlier investigations in an attem pt to outline the physical m echanism underlying the production of a gravitom agnetic field inside a superconductor. Basic to their consideration was an assum ption of near-zero m agnetic perm eability in the superconductor and the requirem ent of coherent alignm ent of lattice ion spins in conjunction with a tim e-varying applied m agnetic vector potential field, W ith this understanding, they determ ined values for laboratory-scale induced internal gravitom agnetic fields and external gravitoelectric fields and how these fields could be m axim ized. However, in 1994 K owitt (Reference 26) claim ed that their 1992 and 1993 results were not credible owing to their assum ption of near-zero perm eability inside a superconductor. However, Li and Torr rather effectively countered shortly thereafter, and W oods (Reference 3) also called that criticism into question. Later, however, Harris (Reference 27) argued in a m ore effective critique that Li and Torr's previous results were erroneous because they assum ed arbitrary (and extrem ely sm all) distances from the lattice ion to the observer, thus producing unreasonably large effects. In fact, Harris pointed out that the correct estim ation of the induced gravitoelectric field outside a superconductor is som e 20 orders of m agnitude sm aller! N o evident rebuttal has been forthcom ing from Li or Torr. At about this tim e, Torr and Li parted com pany, although both continued to work in the area. In 1995, Li was sufficiently convinced that she now had the answer to producing an artificial gravity field that could be m easured outside a superconductor that she approached R. K oczor at N ASA to fund further developm ent of her version of the theory. By this tim e the Podkletnov paper had been "discovered," and a few forward­ thinking N ASA scientists determ ined that perhaps it was tim e to initiate som e research in the area. After all, now there was a peer-reviewed theoretical basis for a peer- reviewed experim ent. Also at this tim e, this author and colleagues began prelim inary experim ents in Toronto after contacting Podkletnov. Our approach was to attem pt to reproduce the 1992 Physica C spinning disk experim ent with additional data from Podkletnov but using a better cryogenic design with the possibility of m echanically spinning the disk. This author and colleagues started m anufacturing our own large YBC O disks in house. The following year, while still at the Tam pere University of Technology's Institute for Materials Science, Podkletnov and Vuorinen attem pted to publish updated spinning disk experim ents in the British Journal of Physics D Applied Phys Vol. 29 (1996), but the paper was withdrawn in a cloud of controversy. It was later published on the Internet (Reference 28) under the authorship of Podkletnov and Levit and then Podkletnov alone. Vuorinen and Levit had coauthored papers on ceram ic processing with Podkletnov previously. This new experim ent involved a large AC levitated 27-cm - diam eter bi-layer sintered YBC O disk spun to 5,000 rpm using two-phase high- frequency radiofrequency (RF ) "rotation" fields and allegedly showed gravitational shielding in the few percent range. The cryostat design was som ewhat better in that there was considerably m ore shielding of the test m ass from buoyancy and therm al 6 UNCLASSI FIED//FOR OFFICIAL USE ONLY UNCLASSI FIED/ / FOR OFFICIAL USE ONL¥ current effects. There was no independent confirm ation that this experim ent actually took place. Vuorinen and Levit had disappeared from the scene when this author asked Podkletnov whether they were available to discuss the experim ent. N evertheless, this author arranged for Podkletnov to visit the Toronto laboratory for prelim inary consultation on the experim ental design to replicate his 1992 Physica C results. Meanwhile, a 1997 University of South C arolina press announcem ent declared that investors were being sought for a "Gravity Generator" technology based on confirm atory experim ents apparently underway at the university involving nonrotating high-tem perature superconductors and RF coils. This m achine would "replace the wheels of a car...lift and propel aircraft, drive generators m ore efficiently and produce gravity-free environm ents on Earth." Evidently, the work of Douglas Torr, who had recently taken up a post there, was the basis for the announcem ent. Unfortunately, the excitem ent was short-lived, as a subsequent announcem ent was issued stating that the previous announcem ent was "prem ature." In prelim inary experim ents at N ASA, K oczor, Li, et al. failed to see expected shielding effect in a Podkletnov-like experim ent (Reference 29). However, they were using a sm all, com m ercially available disk levitated above perm anent m agnets at LN 2 tem peratures. Undeterred, they pressed on, buoyed by the Internet publication of Podkletnov's previously rejected paper and discussions with Podkletnov him self. The following year, N oever and K oczor (Reference 30) published the results of their investigations into nonrotating superconductor disks irradiated by radiofrequencies from 1 to 15 MHz and detected a very weak gravity increase. This finding was later shown by the sam e authors to be the likely result of an instrum entation artifact (Reference 31). In 1999, this author was asked to present the state of the Toronto experim ental replication to the assem bled physicists and engineers at the April 1999 Turin Politecnico m eeting. Gonnelli and others presented their initial findings of a tiny possible weight change in test sam ples suspended above a disk as it passed through Tc. Also presenting was G. Modanese, who had been form ulating his own theoretical explanations for the Podkletnov results. Podkletnov described how the "gravity shielding" effect was discovered. Apparently his group had m ade large sputtering target disks of YBC O for the aforem entioned single-crystal processing, and to ensure the correct uniform ity and porosity, the disk was set into rotation (presum ably m echanically) while being levitated over a "supporting solenoid." This allowed quick and com plete scanning of the target's surface by m eans of a sm all, m ovable test m agnet suspended above the rotating disk and connected to an analytical chem ical balance. W hen the sm oke from a technician's pipe inexplicably appeared to rise above the apparatus, they considered the possibility of gravitational shielding and substituted a nonm agnetic, nonconducting test m ass for the sm all suspended m agnet. N ote that the norm al rotational speeds for m agnetron sputtering are in the tens, not thousands, of rpm . Podkletnov went on to describe his first experim ents with the so-called high-voltage "gravity beam " apparatus. An array of single-crystal whiskers of YBC O was grown on a sm all (few cm 2 in area) substrate using a technique later com m ercialized by m aterials scientists (Professors K ettunen and Tiainen) at the Tam pere University of Technology. This plate was placed upright in a sm all LN 2 dewar and electrically attached to a sm all (~200-kilovolt) van de Graaff m achine. A grounded m etal annular disk was placed a few centim eters laterally away. The whole assem bly was placed in a large bell jar that 7 UNCLASSI FIED/ / FOR OFFICIAL UOE Offff UNCLASSIFIED//TOW OFFICIAL USE ONLY was evacuated and back-filled with argon to prevent YBC O degradation by water vapor. W hen the static m achine was operated, a light blue planar "discharge" was seen to pass from the superconductor array to the annulus. At this instant, a pencil standing upright on a table in an adjoining room and separated from the experim ent by a thick concrete wall fell over. Around this tim e, K oczor had raised som e N ASA funding to com m ission the com m ercial fabrication of a 27-cm bi-layer disk conform ing to Podkletnov and Levit's 1997 specifications. Podkletnov visited the Toronto laboratory for a second tim e to assess the experim ental progress, in particular the fabrication of the special bi-layer sintered ceram ic YBC O disks. Upon persistent questioning about the m ethods he used to power the various coils (without sustaining high-voltage arcs), keep them in phase at high frequencies, and m aintain stability during rotation, it was learned that Podkletnov was not involved in the electrical design but only in the ceram ic side of the experim ent. N evertheless, he claim ed that with our apparatus and "hom e-m ade" disks, one should see the shielding effect, but at a som ewhat sm aller m agnitude than his original results owing to our expected lower rotational speeds. F or several years prior to 1999, Professor Harald Reiss had been working on tests of gravity's influence on high-tem perature superconductors and vice versa as a researcher at Asea Brown Boveri and later the University of W uerzburg in Germ any, where he taught courses in superconductivity. In that year he published (Reference 32) the results of precise m easurem ents of the weights of superconducting and non­ superconducting sam ples cooled below Tc and found anom alies not easily explained away. He weighed sm all, disk-shaped sam ples held in a specially m ade capsule while dipping it into LN 2 and found a slight (~0.5 percent) weight increase of a high- tem perature superconductor for which he was not able to offer a prosaic explanation. W e supplied som e YBC O disks for his experim ents. His analysis of possible artifacts is thorough and very useful to other researchers investigating this area. In 2003, he published (Reference 33) an update of his ongoing LN 2 experim ents with increased precision and artifact reduction. He was still observing weight changes during Tc transition to a repeatable degree not achieved elsewhere. 1999 saw the wind-up of the N ASA sm all-diam eter nonrotating disk experim ents with no unequivocal results. As the budget for such experim entation had been exhausted by the costly fabrication of the 27-cm bi-layer disk, K oczor tried to interest others, including our laboratory, to take on the task of levitating and RF -spinning this m onster disk at LHe tem peratures; we respectfully declined. Around 2002, K oczor gave up trying, as the experim ent was deem ed too difficult without considerable effort, and no spare disks were available in case the only YBC O disk that was m ade broke! Two years later, Podkletnov and his collaborator on theory, Modanese, published a paper on the web concerning an enhanced version of the gravity beam , or "Im pulse Gravity" experim ent (Reference 34). This was the first general publication of the high- voltage im pulse force experim ent. Enough technical description was available to allow an assessm ent of the validity of experim ental setup. Unfortunately, m any unresolved technical questions cast considerable doubt on whether the experim ent actually had been undertaken. N either Podkletnov nor Modanese provided by a shred of confirm atory evidence. However, the paper presented a general sum m ary of the theoretical work by Modanese and included an extensive bibliography. 8 UNCLASSIFIED//FOR OFFICIAL USE ONLY UNCLASSIFIED//TOW OFFICIAL USE ONLY Our own version of the Podkletnov spinning disk experim ent was com pleted in late 2001 and published in 2003 (Reference 35) showing a null result. It represented— and still represents— the closest published replication of the original Podkletnov experim ent. It contains a discussion of the experim ental difficulties arising from the nature of the experim ent itself and highlights the inability of the experim entalist (Podkletnov) to supply critical data on his alleged prior experim ents. Such a lack would have seriously ham pered our replication had not Podkletnov been actively involved in the experim ental setup, at least from the standpoint of the construction of the ceram ic disk. In fact, we sent to Podkletnov in F inland one of our bi-layered disks that he pronounced acceptable for experim entation. Unfortunately, neither Podkletnov's 1992 publication nor subsequent discussions with Podkletnov allowed a com plete understanding of how the original experim ent was carried out. In 2001, Tajm ar and De Matos began publishing a set of theoretical and experim ental papers (Reference 36) that essentially carried on and incorporated Li and Torr's earlier work while also providing additional insights. Martin Tajm ar was a newly m inted post­ doc working at the European Space Research & Technology C entre, Holland. The paper condensed the previous work, including that of Li and Torr, to show that every electrom agnetic field is coupled to a gravitoelectric and gravitom agnetic field and that the coupling "is generally valid and does not require special properties like superconductivity." The authors acknowledged the criticism s of Li and Torr by K owitt and Harris and noted that the sim ple coupling coefficient they derive is exceedingly sm all. However, it can be increased by using m assive ion currents (for exam ple, m oving/ rotating m ass or dense plasm as) and by aligning electron and nuclear spins. In a roughly concurrent publication (Reference 37), De Matos and Tajm ar, now at the Austrian Research C entres, extended their previous ideas and used a Barnett Effect analog to show that "any substance set into rotation becom es the seat of a uniform intrinsic gravitom agnetic field." Som e experim entalists were still not willing to give up on superconductor-m ediated gravity effects, in spite of the failure of our replication and the null results of N ASA and others. In 2002, a few researchers at Boeing Phantom W orks in C alifornia attem pted to interest their m anagem ent in replicating the Podkletnov high-voltage im pulse gravity beam experim ent but were turned down in part because of the publicity resulting from a leaked copy of the internal proposal getting to the m edia. That sam e year, C hiao in C alifornia proposed (Reference 38) using superconductors as gravitational wave transducers into RF radiation and vice versa and attem pted an experim ent that apparently failed. Harris (Reference 39) later rebutted C hiao by stating that neither gravitoelectric nor gravitom agnetic fields accom pany gravitational waves. In his 1950 book on superfluids, London (Reference 40) derived an expression for the m agnetic field produced by a rotating superconductor or superfluid that was proportional to the C ooper pair m ass-to-charge ratio and the angular velocity. This is also called the London m om ent, and its value had been m easured in the laboratory by Tate et al. (Reference 41). A general expression of the London m om ent can be used to determ ine the C ooper pair m ass. In a 2003 paper, Tajm ar et al. (Reference 42) noted that the Tate experim ents showed that the C ooper pair m ass, which had been predicted to be slightly sm aller than twice that of the electron, was actually slightly larger. Intrigued that there had been no published solution to this disagreem ent, Tajm ar asked if a gravitational effect m ight be at work. By applying his previous work to this "C ooper Pair Mass Anom aly," he found that a relatively huge internal gravitom agnetic field 9 UNCLASSI FIED//FOR OFFICIAL USE ONLY UNCLASSIFIED//P8K OFFICIAL U5E ONET would be required to explain the m ass anom aly, a field that m ay be investigated in the laboratory. In fact, he proposed an experim ent "m easuring the torque on a spinning gyroscope produced by the gravitom agnetic field possibly generated by rotating superconductors." His subsequent publications showed that he was convinced that the "anom alous gravitom agnetic London m om ent" can actually be detected in the lab and noted that an experim ent was already underway under his direction. In an attem pt to bring som e order to the discussion about correct laboratory practices in experim ents designed to detect gravity-like forces, Reiss and Hathaway (Reference 43) collaborated on a paper published in 2005. They tried to rem ind experim entalists about the perils and pitfalls in the kind of research docum ented in the present paper. This author m eanwhile presented an extensive list of experim ental issues that is available and is still being added to on the Internet (Reference 9). These issues range from spurious m echanical effects to electrom agnetic and electrostatic effects together with a discussion of signal analysis and instrum entation issues. The following year, Tajm ar et al. (Reference 44) described the results of an experim ent they had perform ed to try to validate their conclusions about the anom alous London m om ent, which they term ed the "gravitom agnetic London m om ent." The experim ent involved spinning niobium and high-tem perature ceram ic superconductor rings at LHe tem peratures. N o external m agnetic fields were applied. They claim ed to have found the expected large gravitom agnetic field as detected by nearby accelerom eters that m atched to within a factor of 1.5 of their theoretical results. Eric Davis at the Institute for Advances Studies in Austin has raised concerns about the theoretical basis for the claim . Davis contends (Reference 45) that the basis for calculating the C ooper pair m ass is still so fraught with uncertainties as to leave Tajm ar's m ass anom aly unfounded. This leaves the theoretical basis of Tajm ar's experim ent in som e doubt. There were also several concerns about the experim ental design and protocol. By 2007, Tajm ar (Reference 46) recognized that new data from im proved experim ents did not m atch their prior predictions. N evertheless, an unexplained residual signal persisted that exhibited several unexpected features, including a relatively large coupling constant of IO-8 between the observed acceleration effect and the applied angular velocity. The effect appears to be proportional to angular m om entum and inversely proportional to tem perature after passing a critical tem perature (which is dependent on the m aterial of the spinning ring and is not coincident with the superconducting critical tem perature). In addition, the effect is m ore pronounced in the clockwise rotation direction (as viewed from above), and it does not decay as a dipole field would. W hile Tajm ar et al. endeavor to address all possible system atic errors or prosaic explanations, they conclude that the "m easurem ents rule out our previous theoretical m odel that predicted a coupling proportional to the m aterial's C ooper pair and lattice m ass density." The residual signal observed in the m ost recent experim ents rem ains unexplained. After Tajm ar et al. considered im provem ents to the apparatus suggested by other researchers, Tajm ar's effect continued to approach the noise floor. Unfortunately, the explanations Tajm ar provided in 2008 (Reference 47) for the residual effects becam e m ore difficult to understand and believe. It is not known whether Tajm ar is continuing the experim entation at present. 10 UNCLASSI FIED/ / FOR OFFICIAL USE ONLY UNCLASSIFIED//FOR OFFICIAL UDE ONLY As of this writing, there have been no further pronouncem ents from Podkletnov. N o one has published a replication of his "gravity beam " experim ent, and as tim e passes, m ore and m ore scientists are com ing to the conclusion that the experim ent was never actually perform ed. C oncerns about experim ental procedures are not confined to the fringe, either. F inal analysis of the Gravity Probe B satellite data is also apparently in serious difficulty (Reference 48), adding weight to the conclusion that experim entation in this area is fraught with difficulty even for the m ost experienced researchers. Conclusion Although the payoff of the discovery of a superconductor-m ediated interaction between m atter and gravity would be trem endous, only a few researchers are pursuing this goal. The m ain reason for this is the adherence to dogm a concerning the im possibility of increasing the m atter/electrom agnetic coupling coefficients. This adherence is reinforced by reputable physicists pointing out that the theoretical constructs presented so far are based on questionable foundations. As with any forays into the unknown, one has to accept a few bum ps along the way, including som etim es going back to the starting point in order to start again. The likelihood of scientific ridicule is extrem ely high in the search for laboratory-scale gravitational interactions. Increased understanding of the nature of high-tem perature superconductivity will be advantageous in setting the firm basis from which to proceed. True scientists will continue to speculate about the ideas considered above, whether outlandish or not. Experim ents will continue until either funding runs out or theory proves unequivocally that the expected effects will be far too sm all to see; however, experim entalists m ust ensure that other researchers have com plete inform ation so they can replicate experim ents. Theory will continue regardless, but theoreticians m ust ensure that the scientific foundations are correct, and experim entalists m ust rem ain wary of potential traps. 1 Gravitational W ave C onference: International High-F requency Gravitational W aves (HF GW ) W orking Group, The Mitre C orporation, McLean, VA, May 2003 2 W oods, R.C ., "Gravitational W aves and Superconductivity," Space Technologies and Applications International F orum 200 5, El Genk, M.S. (ed.) 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Am erican Institute of Physics C onference Proceedings, Melville, N Y, 2005 44 Tajm ar, M., Plesescu, F ., Marhold, K ., De Matos, C ., "Experim ental Detection of the Gravitom agnetic London Mom ent," arXiv: gr-qc/0603033, Mar. 2006 45 E. W . Davis, Institute for Advanced Studies, Austin, TX, private com m unication, 2007 46 Tajm ar, M., Plesescu, F ., Seifert, B., Schnitzer, R., and Vasiljevich, I., "Search for F ram e-Dragging in the Vicinity of Spinning Superconductors" arXiv: abs/ 0707.3806v7 47 M. Tajm ar, Austrian Research C entres, Seibersdorf, Austria, private com m unication, 2008 48 , accesses Jan 25, 2009http:/ /www.newscientist.com /article/ dnl3938?feedld=online-news_rss20 12 UNCLASSI FI ED//TOR OFFICIAL UOE ONte¥