Dick Post with some of the components of his maglev system
The Quest for Energy
June / July 2004
Volume 2 Number 3
Anyone who's ever been intrigued by the seemingly magical properties of magnets should meet Dick Post. Sitting in his office surrounded by a wall-to-wall clutter of books, research papers, reports and gadgets of various shapes and sizes, Post can barely contain his enthusiasm over the latest news about his favorite scientific tool.
"Here, take a look at this," he exults, turning to his computer and calling up a paper reporting on computer simulations of what Post calls a "new wrinkle" in using magnetic fields to tap the fusion energy that powers the sun.
"A few years ago, Dmitri Ryutov of Novosibirsk (Russia) came up with a way to stabilize an axisymmetric (cylindrical magnetic fusion) system," Post says. "It's very elegant, but also very simple. And we now have a real chance to do realistic simulations showing that it works."
While his colleagues at Lawrence Livermore National Laboratory (LLNL) and around the world experiment with high-powered lasers and ponder exotic zero-point energy fields, Post is putting his money on the old-fashioned magnet to help solve the energy needs of the future.
A veteran particle physicist at LLNL, Post has devoted a lifetime to studying magnets in virtually all their forms and applications —€“ from generating all-but-limitless energy via controlled nuclear fusion to providing energy-efficient transportation.
Post, who joined Livermore when the lab was established in the early 1950s, retired in 1992 but quickly realized he still had "unfinished business." At 85, he puts in four full days a week in his office and has no intention of slowing down.
Holder of more than 30 patents and celebrated as the "father of the modern flywheel," Post could easily sit back and rest on his scientific laurels. But he continues to work on magnetic confinement fusion, determined to have the last laugh on skeptics who love to joke that fusion energy is 30 years away and always will be.
Post concedes that the path to fusion energy has been less than smooth. The technical challenges involved in attempting to harness the thermonuclear energy released by hydrogen bombs and the stars have been formidable and political support for fusion research has been fickle.
By the mid-1980s, Post and his colleagues were making good progress in demonstrating the viability of the "open," or "magnetic mirror" approach to fusion. Cylindrical magnetic fields, pinched at their ends like a party popper, were used to confine superheated plasma, a gas consisting of electrons and positively charged hydrogen ions. The goal was to apply enough heat and pressure to allow the hydrogen nuclei to fuse and release more energy than the amount required to heat the plasma.
Government funding dried up, however, and the project was mothballed. Support for fusion research focused on another approach, using huge doughnut-shaped "closed" fusion reactors known as tokamaks. Magnetic mirrors, which were prone to plasma drift and leakage, slipped to the back burner.
But Post and his colleagues persevered, hoping to find a way to achieve controlled fusion that would be smaller and less expensive than tokamaks by sidestepping their chief drawback—€”turbulence.
"In magnetic fusion, you're faced with a turbulent regime," Post says. "You can deal with it either by making the reactor big enough so you can live with the turbulence, which is the tokamak approach, or by finding geometries that have shown low turbulence and making them into a practical fusion system."
That's where the exciting "new wrinkle" devised by Post's Russian colleague Dmitri Ryutov, now at Livermore, comes in. Post believes Ryutov's solution to stabilizing and containing the plasma in an open system —€“ by "anchoring" it in place using small amounts of plasma on the outside of the magnetic field —€“ has the potential to revive magnetic mirror fusion "in a form that would make it much more attractive for a fusion power system. The mirror machine could become the answer that fusion has been waiting for."
While fusion energy remains tantalizingly out of reach for now, many of the other uses for magnets that Post has invented and patented are beginning to find their way into a variety of practical applications. One of the most promising is a simple and efficient way to use permanent magnets to levitate the trains in a mass transit system and eliminate most of the power drain caused by friction. Livermore's "maglev" system uses a special arrangement of powerful magnets known as a Halbach Array to elevate the train above a guideway embedded with close-packed coils of insulated copper wire. Such trains are smooth, quiet, energy efficient, and capable of speeds of more than 300 kilometers an hour.
Physicist Klaus Halbach of Lawrence Berkeley National Laboratory developed Halbach arrays for use in particle accelerators. Arranging magnets so they create a periodic magnetic field that is alternately vertical and horizontal concentrates the field on one side while canceling it on the opposite side. A Halbach Array can levitate a weight 50 times heavier than its magnets.
Post said the maglev system, recently licensed by General Atomics of San Diego using the trade name Inductrack, is moving toward a large-scale demonstration. He said Inductrack is "nowhere near as complex" as the maglev systems currently being tested in Germany and Japan.
Inductrack requires neither the costly cryogenic cooling systems needed by the superconducting magnets in the Japanese system, nor the complicated sensors and feedback circuits of the German system. What's more, Inductrack trains would be inherently stable and safe: In the event of a power failure, they would coast smoothly to a stop and settle back on their auxiliary wheels. Post said they're also particularly well suited for low-speed urban mass transit systems, because they can accelerate rapidly and easily handle steep grades and tight turns.
The idea for magnetic levitation grew out of Post's research on electromechanical batteries, which use circular Halbach arrays, advanced flywheels, and nearly frictionless "passive" magnetic bearings (invented by Post, naturally) to store energy much more efficiently than conventional electrochemical batteries.
Flywheels first captured Post's attention "as a sidelight" in the early 1970s, when he and his son Stephen, an electric car buff, wrote a seminal article for Scientific American suggesting that flywheels made of composite materials instead of metal could be used to store energy in electric vehicles.
Post's flywheel battery technology was licensed to a San Francisco company in 1994, and is currently being developed for such applications as uninterruptible power supplies for computers and other sensitive electronic equipment, and to provide energy storage for wind and solar power systems.
The licensee has also received funding from the federal government to develop hybrid diesel-electric buses and trucks using flywheels in a program designed to reduce lung-damaging particulate emissions from diesel engines by 90 percent and cut diesel fuel consumption in half.
Manufacturers of hybrid automobiles, however, have yet to adopt flywheel batteries; both Toyota and Honda use electrochemical batteries in their popular gasoline-electric hybrid cars. Post remains convinced that flywheel batteries are a better idea.
"Somebody should really take the flywheel seriously for hybrid vehicles," he said. "Flywheel batteries are over 92 percent efficient in returning the energy put into them, versus 70 to 85 percent for an electrochemical cell.
"They should also have a very much longer life than an electrochemical battery.
"In fact, in terms of energy efficiency," Post said, his eyes twinkling, "a vehicle that uses hydrogen fuel cells and a flywheel battery would be an excellent combination—€¦"
To someone like Dick Post, the appeal of saving that much energy can only be described as—€¦well, magnetic.
Charles Osolin is an LLNL public information officer.
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