Greg East Santee, Ca USA - Sunday, October 24, 1999 at 15:42:45 (PDT) I'm new to Weird Science, but not new to strange science phenomena. I was quite impressed with Bill's article on "Energy-sucking Radio Antennas". Since I've already built a small DC PM motor which continuously runs day and night fueled by emissions from a local AM radio station, I thought I'd try to augment the system by partially invoking the capacitive plate antenna scheme outlined in the above paper. I took two 2'X 4' sheet metal plates, one on the ground, the other atop a plastic trash can placed on the first piece....separation about 1 meter vertical. This big air-capacitor was placed in parallel with, an already, carefully tuned loop antenna. This loop antenna is configured to store power via germanium and zener diodes and yields about 8VDC on a capacitor...enough to occasionally flash a red LED when touched to the capacitor. Adding the capacitive antenna and re-tuning to best resonance allowed the metal plates to become part of the resonant circuit and added a healthy 5 to 6VDC to the capacitor. I now have a two-transistor circuit flashing the LED. I was very careful to test every hook-up scheme of the plates to insure that they were NOT simply adding to the length of the loop portion of the antenna. I believe that I have witnessed the action of a resonant capacitive plate antenna drawing static charge from the Earth's static field. I say this because I did not experience an increase in curent, just an increase in voltage. I highly recommend that you all read Bill's paper on ' Energy-sucking antennas' as well as his paper "On the Possibility That Electromagnetic Radiation Lacks Quanta of Any Kind -or- photon dies screaming". Just thought I'd share. -------------------------------------------------------------------- Date: Sun, 01 Aug 1999 10:13:46 -0400 From: John Denker Subject: Re: teeny atoms absorb huge EM waves To: PHYS-L@LISTS.NAU.EDU At 02:15 PM 7/29/99 -0700, William Beaty wrote: >I've always been befuddled by the ability of atoms and molecules to >intercept waves which are >> than the diameter of the atom. Those waves >refuse to pass through an atom-sized pinhole. Why then are they blocked >by an atom-sized obstruction? > >Here's a possible answer. In a paper on VLF radio receivers, the authors >pointed out that small antennas will absorb large amounts of propagating >EM energy if the antenna is connected to a resonant circuit. As energy >builds up in the resonator, an AC field appears around the antenna, and >this field interacts coherently with the received waves as if the antenna >was much larger than it actually is. That's true, and it's part of the answer to your question. >At first glance this seems silly. How can an *oscillator* enhance the >process of EM absorbtion? It doesn't seem silly to me. Consider the AR (anti-reflective) coating on lenses. How can adding another layer "suck" more light into the lens? But it does. It's classic (and classical) wave mechanics. >A resonant circuit would transmit at the same time it receives! Absolutely it does. Any absorber does. There's a paper by Feynman and Wheeler on this. (One of the first scientific papers Feynman ever wrote, IIRC.) > At the very least, the waves from such a transmitter >would simply superpose with the received waves and have no effect. EM >fields obey superposition. By transmitting, I cannot affect the waves >which are already propagating past my transmitter, since one wave won't >interact with another. But wait... if the transmitter is phase-locked in >lagging phase with the incoming radiation, then it would partially cancel >the EM fields of the incoming wave, and the volume of this "cancelling" >effect would be larger than that of a passive antenna. Right. And if you carry out the calculation you just described, you will derive the optical theorem. As the name suggests, it is completely classical wave mechanics. OTOH since hardly anybody studies classical wave mechanics any more, you may find it easier to find a discussion in your quantum mechanics books. >Aha, EM is *not* linear where power is concerned. There's an e^2. That's for sure. >If the above is true, then at its resonant absorbtion frequency, an atom >would act much larger than it actually is. In a wave-based model, the >atom would be surrounded with oscillating fields, and these fields would >extend the reach of the tiny atom. It would behave more like a half-wave >dipole antenna than like a pinhole where the diameter << wavelength. That's all true, except for the emphasis on resonance. In the Born approximation, the scattering power depends on the size *and* on the depth of the scattering potential. You can have a delta-function shaped scatterer with zero size and quite hefty scattering. The pinhole scatterer is small *and* not very deep. > Modern radio >receivers would not employ this effect, since their antennas are decoupled >from any resonant circuits by the input amplifier stage. (We want our >antennas to be relatively broad-band, not sharply tuned.) Radio receivers wouldn't benefit. They care about signal-to-noise ratio, not absolute signal energy. (To say it another way: nowadays the noise temperature of the RF preamp is really, really low.) A tuned antenna would resonate with noise just as well as signal. Receivers can cut down the noise bandwidth electronically just as well as they could with a resonator. >How would I perform calculations on this system to show that extra energy >would flow into an oscillating antenna? Use a numerical simulation of the >near-field space around a short dipole antenna? (Gah!) Read up on * Optical theorem * Born approximation * Hugyhens' construction. I saw a manuscript that David A. B. Miller wrote a few years ago on this, showing that the usual hand-wavy version of H.C. could be made quite rigorous. I don't know if/where that got published. If you can't find it let me know and I'll bug DABM for it. -------------------------------------------------------------------- Date: Thu, 29 Jul 1999 14:15:57 -0700 (PDT) From: William Beaty To: list physics teaching Subject: teeny atoms absorb huge EM waves I've always been befuddled by the ability of atoms and molecules to intercept waves which are >> than the diameter of the atom. Those waves refuse to pass through an atom-sized pinhole. Why then are they blocked by an atom-sized obstruction? Here's a possible answer. In a paper on VLF radio receivers, the authors pointed out that small antennas will absorb large amounts of propagating EM energy if the antenna is connected to a resonant circuit. As energy builds up in the resonator, an AC field appears around the antenna, and this field interacts coherently with the received waves as if the antenna was much larger than it actually is. At first glance this seems silly. How can an *oscillator* enhance the process of EM absorbtion? A resonant circuit would transmit at the same time it receives! At the very least, the waves from such a transmitter would simply superpose with the received waves and have no effect. EM fields obey superposition. By transmitting, I cannot affect the waves which are already propagating past my transmitter, since one wave won't interact with another. But wait... if the transmitter is phase-locked in lagging phase with the incoming radiation, then it would partially cancel the EM fields of the incoming wave, and the volume of this "cancelling" effect would be larger than that of a passive antenna. Aha, EM is *not* linear where power is concerned. There's an e^2. It's like "antisound," where an emitter can act like an absorber or a reflector. By superposing another coherent EM field upon the incoming waves, perhaps I can redirect their Poynting vector field so that it points at my transmitting antenna. If I "transmit" coherently from a small antenna, then my transmitter can act transparent, or like an absorber, or like a reflector, depending upon the phase of the transmitted wave. And, since the size of the antenna is far smaller than one wavelength, the antenna alone would not radiate much energy except when it is interacting with an incoming wave. If the above is true, then at its resonant absorbtion frequency, an atom would act much larger than it actually is. In a wave-based model, the atom would be surrounded with oscillating fields, and these fields would extend the reach of the tiny atom. It would behave more like a half-wave dipole antenna than like a pinhole where the diameter << wavelength. Has anyone on phys-L encountered this idea? It seems very weird, but it does connect with other things I understand about EM. Modern radio receivers would not employ this effect, since their antennas are decoupled from any resonant circuits by the input amplifier stage. (We want our antennas to be relatively broad-band, not sharply tuned.) This resonance effect, if it exists, should apply to the old "super-regenerative" detectors. I'd always assumed that a super-regen radio was simply an exotic type of amplifier, not a device which actually *receives* more energy than a passive antenna would. How would I perform calculations on this system to show that extra energy would flow into an oscillating antenna? Use a numerical simulation of the near-field space around a short dipole antenna? (Gah!) ((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billbeskimo.com http://amasci.com EE/programmer/sci-exhibits science projects, tesla, weird science Seattle, WA freenrg-L taoshum-L vortex-L webhead-L -------------------------------------------------------------------- Date: Sun, 1 Aug 1999 23:01:28 -0700 (PDT) From: William Beaty To: "Forum for Physics Educators" Subject: Re: teeny atoms absorb huge EM waves On Sun, 1 Aug 1999, John Denker wrote: > At 02:15 PM 7/29/99 -0700, William Beaty wrote: > >I've always been befuddled by the ability of atoms and molecules to > >intercept waves which are >> than the diameter of the atom. Those waves > >refuse to pass through an atom-sized pinhole. Why then are they blocked > >by an atom-sized obstruction? > >At the very least, the waves from such a transmitter > >would simply superpose with the received waves and have no effect. EM > >fields obey superposition. By transmitting, I cannot affect the waves > >which are already propagating past my transmitter, since one wave won't > >interact with another. But wait... if the transmitter is phase-locked in > >lagging phase with the incoming radiation, then it would partially cancel > >the EM fields of the incoming wave, and the volume of this "cancelling" > >effect would be larger than that of a passive antenna. > > Right. And if you carry out the calculation you just described, you will > derive the optical theorem. As the name suggests, it is completely > classical wave mechanics. OTOH since hardly anybody studies classical wave > mechanics any more, you may find it easier to find a discussion in your > quantum mechanics books. Bingo, I went to the UW physics library on friday and found some references on this. One is: Craig F. Bohren, "How can a particle absorb more than the light incident on it?" Am. J. Phys, 51(4) Apr. 1983 pp 323-327 In his intro, Bohren points out a misconception associated with this topic: To those who first encountered in neutron physics the concept of the area that a target presents to a projectile (i.e., its cross section), it comes as no suprise that targets can sometimes extend beyond their strict geometrical boundaries, even greatly so. Indeed, the very unit for neutron cross sections, the barn, encourages one to think big. But photons are supposed to behave more soberly than neutrons; every physics student knows that photons travel through free space mostly in straight lines, although they do sometimes exhibit a bit of waywardness in the vicinity of edges. Notions about what photons can and cannot do are formed in traditional optics courses, which emphasize visible light interacting wtih large bodies, usually transparent. With time these notions become deep-seated prejudices and are often difficult to dislodge. Yet it is incontrovertible that there are many circumstances, by no means exotic, under which small particles (smaller than the wavelength) can absorb more than the light incident on them. My first task in this paper is to examine some of these circumstances. Then I shall give a pictorial representation of absorbtion of light by a particle in a way which, to the best of my knowledge, has not been done before. Bohren goes on to analyze the Poynting field around a small metal sphere at UV frequencies where surface plasmon resonance cause significant absorbtion, and around a NaCl sphere at IR frequencies where surface phonons are the absorbers. His results are very interesting. Also interesting is that there are very few papers on this topic. Looks like a possible "hole in physics", where a widespread misconception diverts our attention from an interesting phenomenon. > >Aha, EM is *not* linear where power is concerned. There's an e^2. > > That's for sure. > > >If the above is true, then at its resonant absorbtion frequency, an atom > >would act much larger than it actually is. In a wave-based model, the > >atom would be surrounded with oscillating fields, and these fields would > >extend the reach of the tiny atom. It would behave more like a half-wave > >dipole antenna than like a pinhole where the diameter << wavelength. > > That's all true, except for the emphasis on resonance. In the Born > approximation, the scattering power depends on the size *and* on the depth > of the scattering potential. You can have a delta-function shaped > scatterer with zero size and quite hefty scattering. The pinhole > scatterer is small *and* not very deep. Small particles might act as larger scatterers, but doesn't scattering behave differently near a resonance? Bohren's paper concentrates on absorbtion rather than scattering. He offers a 2D plot of the Poynting field around a tiny aluminum sphere at the resonant frequency of 8.8eV and at an off-resonance frequency of 5 eV. Very interesting! At the non-resonant frequency, the Poynting field passes the sphere almost as if it was not there. The lines of energy-flow are parallel except within one radius of the sphere, where they temporarily spread apart and then close behind it without touching its surface; much like a fluid flow around an object at very low Reynolds number. He gives the absorbtion efficiency as 0.1, as if the sphere was *much smaller* than its geometrical area. At resonance, the depicted Poynting field is very different. Lines of energy flow which were far from the axis through the sphere are bent inwards and hit the surface of the sphere. The sphere is "funneling" energy into itself and acting as a much larger object. Bohren estimates that the absorbtion cross-sectional area is 18 times larger than expected, and the "absorbtion radius" is 4.2 times greater than the geometrical radius. I had suspected that something strange might occur at resonance, but I didn't expect that an object would act *smaller* than its geometrical size at off-resonant frequencies. ((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billbeskimo.com http://amasci.com EE/programmer/sci-exhibits science projects, tesla, weird science Seattle, WA freenrg-L taoshum-L vortex-L webhead-L Date: Mon, 2 Aug 1999 00:41:27 -0700 (PDT) From: William Beaty To: "Forum for Physics Educators" Subject: Re: teeny atoms absorb huge EM waves On Sun, 1 Aug 1999, John Denker wrote: > At 02:15 PM 7/29/99 -0700, William Beaty wrote: > > Modern radio > >receivers would not employ this effect, since their antennas are decoupled > >from any resonant circuits by the input amplifier stage. (We want our > >antennas to be relatively broad-band, not sharply tuned.) > > Radio receivers wouldn't benefit. They care about signal-to-noise ratio, > not absolute signal energy. (To say it another way: nowadays the noise > temperature of the RF preamp is really, really low.) A tuned antenna would > resonate with noise just as well as signal. Receivers can cut down the > noise bandwidth electronically just as well as they could with a resonator. Yep, the original article was on VLF/ELF research, where the signals are low, the bandwidth small, and receivers must use long integration times in order to get the received energy up above the noise energy of the input stage. Increasing the received energy would be useful in this situation. Whenever it's inconvenient to add front-end amplifiers to an RF receiver, and where the antenna is much smaller than one wavelength, we could increase the "effective size" of the antenna by adding a resonant circuit. I've been told that common AM radios use antenna-tuning. This clears up a question I've always had about AM radios: how can they get away with such a small antenna? Do they simply have immense front-end gains? Maybe not. If their ferrite loop antenna is tuned to the received frequency, then it will create its own EM field, and take advantage of the same "energy sucking" effect that atoms use to grab light waves. A portable AM radio is like a "giant atom". > >How would I perform calculations on this system to show that extra energy > >would flow into an oscillating antenna? Use a numerical simulation of the > >near-field space around a short dipole antenna? (Gah!) > > Read up on > * Optical theorem > * Born approximation > * Hugyhens' construction. I saw a manuscript that David A. B. Miller > wrote a few years ago on this, showing that the usual hand-wavy version of > H.C. could be made quite rigorous. I don't know if/where that got > published. If you can't find it let me know and I'll bug DABM for it. That reference sounds like it would be a good place to start. Below is a very crude, 1-dimensional model of a real-world receiving antenna with and without a resonator. Suppose I transmit a VLF signal at 1KHZ with a transmitting antenna at 10 megavolts and 100km distance from the receiver. If my receiving antenna is a plate suspended 1m from a ground-plane, then we form a capacitive voltage divider as shown below. If the receiver antenna's capacitance is 10pF, and the capacitance between that antenna and the transmitter is 1/10,000 times smaller ( 1m / 100Km ) then the signal on the receiver is 100 volts, but with a very large impedance. I'll put a load resistor on the receiving antenna that matches the divider's series capacitance (so that I can draw significant energy from it.) The divider's capacitance is dominated by the 10pF between antenna and ground. This gives a 1/(2*PI*F*C) = 16 megohm load resistor, and it drags the received voltage down from 100V to 70V. The energy received by this antenna is 300 microwatts. __________ --> | 10 MVolt |_______ | @ 1KHz | | |__________| | | ___|___ Capacitance from transmitter to receiver _|_ ( very small, say 1/10,000 pF ) //// _______ | | receiving |______________ <--- 70.7V @ 1KHz antenna | | (metal plate) ___|___ \ 10pF / 16 Megohm _______ \ | / |______________| _|_ //// Now lets add a tuned circuit: __________ --> | 10 MVolt |_______ | @ 1KHz | | |__________| | | ___|___ Capacitance from transmitter to receiver _|_ ( very small, say 1/10,000 pF ) //// _______ | | |_____________ | | antenna | \_ (metal plate) ___|___ (_) 10pF (_) Coil _______ (_) | (_) | / |____________| | _|_ 1KHz resonance //// At resonance the 10pF capacitance vanishes, since an ideal parallel- resonant circuit looks like an infinite resistor. The capacitive voltage-divider is no longer there. How high will the antenna's voltage rise? To ten megavolts! (But only if we stay with this crude 1-D model.) If the coil's resistance is very small (Q is incredibly high) then the voltage on the tuned circuit will rise until it reaches the same voltage relative to ground as the distant transmitter. However, voltage is not power, and it might take months to build up that much voltage across an ideal resonator. Let's put a resistor across the tuned circuit so we create a flow of real energy and drag the voltage down to .707 of the unloaded voltage. The resistance should equal the impedance of the series capacitance ( 10 ^ -16 uF) or 1600 giga-ohms. Power intercepted by the previous receiver was 300 microwatts. In this receiver it has risen to 30 watts, or ten thousand times higher than the earlier circuit which lacked a resonator. Now for my dirty secret. The original paper was: J. Sutton and C. Spaniol, "An Active Antenna for ELF Magnetic Fields", PROCEEDINGS OF THE 1990 INTERNATIONAL TESLA SYMPOSIUM. It was inspired by N. Tesla's scheme for transmitting significant electrical energy without wires. Throughout his writings, Tesla harps on the fact that his small resonant receivers "draw energy" from incoming EM waves. Now I'm finally starting to see what Tesla was talking about. The "absorbtion radius" of antennas which are far smaller than a wavelength can be greatly increased by connecting them to a high-Q resonant circuit. Tesla's wireless-power idea sounds crazy, yet apparently it employs the same physics whereby tiny atoms can absorb/radiate EM waves of wavelengths thousands of times larger than the diameter of the atom. Here's another way to look at it. If a ground-referenced antenna wire intercepts a particular displacement-current from an EM wave, it will develop a particular voltage relative to ground, and if V and I are in phase (resistor load), then the total absorbed power is V*I. The power is tiny, as would be expected from a normal radio antenna. Now if we were to artificially impress a large AC voltage on the antenna with the same phase as before, and if the same displacement-current is still intercepted by the antenna, then V*I is greatly increased because V is greatly increased. Voltage is not energy, and if the antenna is far smaller than one wavelength (which limits energy loss by RF emission), we need very little energy to put a huge voltage on our receiving antenna, yet the energy absorbtion rate is dramatically increased. A resonator stores the received energy and uses it to create a huge AC voltage on the antenna wire, and therefor to "funnel" or "suck" energy out of the EM wave. Here's another reference, and a portion of the paper's intro paragraph: H. Paul and R. Fischer "Light Absorbtion by a dipole", SOV. PHYS. USP., 26(10) Oct. 1983 pp 923-926 In the so-called semiclassical radiation theory the atoms are described quantum mechanically, while the radiation field is considered as a classical quantity. Such a treatment appears to be justified in case of strong fields, as they are, in particular, generated by lasers. (In fact, this procedure has proved to be very successful in Lamb's famous gas laser theory(1).) Specifically, in the process of light absorption by a two-level atom in the physical picture provided by the semiclassical theory is as follows: The field induces and oscillating electric dipole moment, in the sense of a quantum mechanical expectation value, on the atom, and the total energy flow into the atom is given by the work done by the field on that dipole. Note that in this model absorption appears as a continuous process. This description of light absortion is in close correspondence to classical electrodynamics, the main difference, however, being that the amplituide of the induced dipole moment, contrary to that of a harmonic oscillator, can grow, with time, up to a maximum value only (given by the transistion matrix element for the electric dipole operator), irrespective of how intense the incident field might be. Clearly, this feature reflects the saturation effect present in a two-level system. When calculating the energy flow into the atom, along the lines mentioned, one arrives at the result that its maximum value (corresponding to the maximum value of the induced dipole moment) is larger, by orders of magnitude, than the energy flow in the (undisturbed)incident field throught the geometric atomic cross section. (A typical example is presented in Sec. III.) From this, one must conclude that an atom has the ability to "suck up" energy from a spatial region that is by far larger than its own volume. One might put the question as to the underlying specific physical mechanism. Acutally, an answer is readily given in the framework of classical electrodynamics. An oscillating dipole generates a wave, in any case, the difference between absorbtion and emission, as a net result, being brought about only by the different phase relations between the incident and the emitted wave. Specifically, in the absorptive case this phase relation gives rise to the effect that the lines of energy flow in the total field are "bent" in a rather large neighborhood of the atom such as to direct the energy flow into the atom. It is the aim of the present paper to give a detailed picture, based on a numerical study, of this bending phenomenon which has been discussed qualitatively already by Fleming(2). So, apparently black holes aren't the only thing in physics that "suck"! :) ((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billbeskimo.com http://amasci.com EE/programmer/sci-exhibits science projects, tesla, weird science Seattle, WA freenrg-L taoshum-L vortex-L webhead-L Date: Fri, 30 Jul 1999 15:04:24 -0700 (PDT) From: William Beaty To: sciclub-list@eskimo.com Subject: tiny atoms emit huge light waves? Mark Kinsler 07/29 5:07 PM wrote: > Insofar as I know, atoms do not absorb long wave radiation. They'll > absorb light and x-rays and frequencies that are on the order of their > size, but I don't think they do much of anything at, say, UHF. By "long wave" I mean wavelengths which are far larger than the size of atoms. Aren't atoms much MUCH smaller than optical wavelengths? Now I'll have to make certain of this by looking for a reference which quotes the diameters of various neutral atoms. If I'm remembering correctly, atoms are on the order of a fraction of a nanometer across, while the wavelength of their emission spectra is hundreds or thousands of times larger than this. How can such small antennas emit large amounts of EM energy? Perhaps the nonlinearity of QM explains the mystery. Or perhaps am I wrong about the diameter of atoms, and instead am remembering the typical lattice-spacing of solids rather than the approximate diameter of individual atoms? If most atoms are hundreds of nanometers across, then there is no mystery here. QM might explain how small atoms can emit large waves, but "Quantized" is not necessarily "nonlinear." A single-frequency photon behaves as a sinusoidal EM wave of infinite temporal extent, just like an AM radio tower broadcasting a blank carrier. No glitches in the time domain, even though that photon is radiated and absorbed in essentially zero time. I note that Laser light acts linear, like radio waves, and produces nice smooth sinusoidal interference fringes even though the image of those fringes might be composed of pointlike photon interactions on the film/phosphor/retina. Nonsinusoidal periodic waves and especially pulses are nonlinear, but both of these possess broad spectra. An extremely narrow spectrum usually signifies a linear process and a high-q resonator, therefor I maintain my suspicions that the narrow emission spectra of atoms is *not* entirely explained by appeals to the nonlinear character of quantized interactions. If atomic emission acted nonlinear, then the lines of an emission spectrum would not be so narrow. Something is weird here. Are atoms like antennae, or like photon-guns? If a system can be usefully modeled using either waves or particles, then the probability functions of the particle-based model are no more nonlinear than the EM fields of the wave-based model. However, I rarely hear people seriously discussing atoms as if they were tiny antennae. They mention this, but don't ever go into details. This seems odd to me. As a result, when I encounter talk about tiny antennae which absorb radiation with unexpected efficiency, it makes me sit up and take notice, because *perhaps* it answers some questions I have regarding a wave-oriented model of atomic emission/absorbtion. Tiny pinholes will not pass light if the wavelength >> pinhole diameter. Conversely, tiny particles should not efficiently absorb light if the particle diameter is >> wavelength. How do atoms do it? ((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billbeskimo.com http://amasci.com EE/programmer/sci-exhibits science projects, tesla, weird science Seattle, WA freenrg-L taoshum-L vortex-L webhead-L