Adding to the technological wish list.

Adding to the technological wish list

Threat one conductor through the hollow of another cylindrical conductor, separate them with an insulator (dielectric) such as Teflon and you'll have a coaxial cable. They're great for transmitting telephone and television signals because they neither produce, nor are influenced much by, external electromagnetic fields. Electrical engineers Christopher Rose and Mike J. Gans at AT&T Bell Laboratories in Holmdel, N.J., report theoretical calculations suggesting that a future superconducting coaxial cable made with a magnetically levitated core could transmitt data at a rate of 100 billion bits per second over a distance of 600 kilometers, or about 375 miles. Today's optical fibers can reliably transmit data at this rate but only one-tenth as far. Cut the data rate by a tenth, and the future cable's reliable transmission distance stretches to 37,500 miles, or 1-1/2 times around the planet.

Passing resistance-free current through the cable would create magnetic forces between the cable's two concentric superconductors. When the core conductor is placed slightly lower than the cablehs geometric center, the net magnetic force is upward and will levitate the conductor, the researchers argue in a paper submitted to IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES. The cable would be free of the transmission losses associated with the insulating support that otherwise would have to be inserted between the conductors, Rose points out. For practical applications, superconductors that work at room temperatures or above and that form into long cables will have to come along.