Would very fine metallic powders have any value as opposed to solid material? e.g. as in Colman_Gillespie?
Definitely. The advantage of passivated and compressed fine powders over solid metals is their increased resistivity without affecting their density much. High resistivity is good because it increases the penetration of the nanopulses into the gain medium. With low resistivity, the RF penetration into conductor is equal to: D = 503292 * SQRT( R/(f*μ r) ) where D: skin depth in mm, R: resistivity in Ωm, f: frequency in Hertz, μ r: relative permeability Which for solid copper means that a 100MHz RF signal penetrates it only 6.5μm deep before it is attenuated 63% (or 26μm for 98% attenuation). So the skin-effect is a major enemy that prevents large volumes of the gain medium matter from being penetrated and excited. Powderization and passivation increases the resistivity of the gain medium to a point where the skin-effect is mitigated. Electric current composed of very fast electrons does not require a conductive chunk of metal, thus high resistivity does not have a negative impact on it like it would have on ordinary slow conduction electrons. P.S. At lower frequencies the RF penetrates deeper so even a solid brass or copper rod/pipe/sheet should work as the gain medium. The presence of a copper pipe inside a transformer (or coil) is often met with objection on the basis that it constitutes a shorted winding, which kills most of the transformer action through shielding via eddy currents / Lenz effect. This objection is not applicable here, because the "copper pipe" acts as a source of the electric current and the resulting magnetic field (like a primary winding) not as a shorted secondary winding.
« Last Edit: 2013-05-01, 14:44:11 by verpies »
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Topic: DSRD pulse generator (Read 200842 times)
