In an article published at Counterpunch on May 28, Michael Dickinson described the microwave crowd dispersal device being produced by the Raytheon corporation . I want to offer some suggestions on countermeasures. First, let me give a brief description of the nature of this device.
Today, we are familiar with microwave cooking. In this process, electromagnetic radiation with wavelengths in the range of millimeters to centimeters penetrates food and causes the heating of its molecules. Since most “food” contains water, it is primarily this molecule that is heated. However, many molecules with similar physical dimensions as regards the bond lengths between atomic nuclei can be similarly heated. The physics is as follows.
Molecules are constructed by individual atoms linked by chemical bonds into geometric structures. Water is H2O, one oxygen atom linked by two (covalent) bonds to two hydrogen atoms, the arrangement being a V with an inside angle of just under 105 degrees. The distance between nuclei is of the order of an Angstrom, which is about one over ten to the tenth power of a meter (or about ten nano-centimeters). The atoms at each end of each chemical bond in the water molecule are different (hetero-polar), so there is a slight difference in the electrical charge from one end of the bond to the other. This has to do with the intricacies of how the electrons (light weight, negatively charged orbiting particles) of the individual atomic nuclei (relatively massive and positively charged) now orbit the nuclei of the molecule, as a composite structure. This charge imbalance would cause the molecule to move to align itself with an imposed electric field. If the electric field alternates, then the molecule can be set into an alternating motion, such as a rotation about the midpoint of a chemical bond as if it were a solid link; or a vibration as if the bond were a spring. This is how the alternating electric fields of microwaves, with frequencies of tens to hundreds of giga-hertz (GHz; 1 Hertz = 1 cycle per second), excite molecules. Molecular motion is heat; it is the accelerated motion of molecules in a body of material that is experienced as heat. The excited molecules more rapidly collide with their neighbors and the boundaries containing the material, and this effect has the macroscopic effects we call pressure and heat.
You may note that your microwave oven has a mesh built into the window of the door. This mesh is an electrically conducting material (metal) which has holes smaller then the wavelength of the microwaves being produced. Because the holes are smaller than the wavelength, the mesh will “appear” as a continuous sheet of conducting material to the microwaves within the oven (cavity), and act as an effective “ground plane” or shield that “shorts out” the electric field of the microwaves, and prevents their escape. The purpose of the holes are to enable you to see into the oven while it is operating. Clearly, if the holes are larger than the wavelength of any electromagnetic radiation produced in the microwave oven, then that short-wavelength portion would escape. So, the door mesh is an important safety device, and we can (should) expect that such a similar mesh is embedded within the oven walls. (Note to “writers”: repetition is the essence of pedagogy.)
The crowd dispersal device is basically the beaming of a microwave oven environment to a remote location. Does Raytheon just remove the containment mesh from one wall and let the microwaves leak out? That is too inefficient. Instead, an elaborate arrangement called a “phased array antenna” is use. A phased array antenna is the combination of many individual antennas (simple electromagnetic oscillators) in close proximity, but each triggered in such a way so that the combined emission from the array has a beam-like property. If you imagine several children patting the surface of the water in a bathtub in such a way that the combined effect adds up to one big wave, as opposed to each of their wavelets interfering with each other to little effect except to produce a frothiness without significant variation of water level, then you see the concept. The mathematics of beam production is implemented by elaborate circuits powering many small antenna nodes (the children), and controlled — or “phased” — by computers.
By these means, the electromagnetic environment of a microwave oven can be broadcast, or projected to some distance. This is the “pain ray” device developed for the US military. Obviously, the degree of discomfort and destruction that can be had depend on the available power. A practical crowd dispersal device requires a reasonable means of transport, hence a truck or “humvee.” This suggests that the power source for the device is limited to the engine of the transporter (perhaps driving an electric generator). Given the efficiency of the process, and the magnitude of the transporter’s motor, we then have the means of determining the effective range of the device (where we must also know some “effective” power density at the “target”).
Fine, but how do you thwart it? The best protection is distance, just don’t be the target! However, if one wishes to engage in a demonstration and be protected from this device, the best protection would be your own electromagnetic shielding or “Faraday cage.” If you are within a conducting mesh (a Faraday cage), where the mesh openings are small with respect to the incident radiation, and with a ground wire that leads intercepted electromagnetic energy away from you, then you are safe. This remedy is not likely to be convenient, but then, perhaps creative talents can find effective refinements of this concept. A suit of armor with chains trailing from your ankles to leak currents into the ground may not be ideal protection. However, plastic shields with embedded meshing, even aluminum foil or aluminized mylar (shiny garbage bags?), behind which individuals could stand (huddle?, crouch?) might allow people to thwart the intent of the device. Once people understand the physics being used against them, they may be able to to fashion materials readily available to them into effective countermeasures; this requires some planning.
Given that a popular assembly might plan to protect itself from a heat ray crowd dispersal device by arming itself with body-length protective shields, and Faraday suits, could they also use their shields as reflectors and “phase array” them to return the beam back to its source? This calls to mind the story of Archimedes’ heat ray, during the siege of Syracuse during 214-212 BC. The Roman historian Lucan wrote that during the siege of the city by Rome, Archimedes had the defenders of Syracuse align their bronze and copper shields, which had been highly polished, so as to reflect sunlight on the attacking ships, which burst into flame. Modern experiments aimed at duplicating this effect show that the effect is most likely with many reflectors, ideal weather conditions and orientation of objects with respect to the sun, and with highly combustible materials and coatings (e.g., wood varnishes) at the targets. For a phalanx of our popular action Faraday Knights, the equivalent might be using the concave (perhaps parabolic) sides of their protective and reflective shields (without grounding wires, and with insulated handles for their users) to redirect the incident microwave radiation back to its source, or thereabouts.
Of course, it bears realizing that any successful countermeasures to crowd dispersal ray devices are guaranteed to move the authorities to escalate to more lethal measures of control. For a continuing revolution, this is simply another level of planning.
MANUEL GARCIA, Jr. is a physicist beyond employment; e-mail at mango@idiom.com