World's Most Powerful Magnet Under Construction

Sept. 11, 2008 -- Using the strongest materials known to man, scientists are building the most powerful electromagnet in the world -- one that won't blow up a split second after it's turned on.

The entire magnet will be a combination of coil sets weighing nearly 18,000 pounds and powered by jolts from a massive 1,200-megajoules motor generator. Once activated, the new magnet should be about two million times more powerful than the average refrigerator magnet.

"The new magnet at the High Field Lab is a fantastic leap forwards in terms of our capability as a scientific community to explore materials under extreme conditions," said Ian Fisher, a scientist at Stanford University.

"In several cases one needs to go to these sorts of extremes to fundamentally understand materials" used in high-temperature superconductors and other applications, said Fisher.

The electromagnet consists of two parts. The outer section, or outsert, will be a cylinder, 1.5 meters (4.9 feet) in diameter and 1.5 meters tall, and solid except for a small hole, less than 8 inches wide, bored through the middle.

Inside that hole rests the insert, nine coils made of copper and strengthened with silver wire as thin as 100 atoms across. Together, the copper and silver create the strongest material known to man, according to Greg Boebinger, Director of the National High Magnetic Field Laboratory in Florida. The magnet is being built at the Los Alamos National Laboratory.

The pressures generated inside the insert will be equivalent to 200 sticks of dynamite going off together, or about 30 times the pressure at the bottom of the ocean.

Very few things can survive those kinds of forces for long -- including the new magnet.

The scientists expect each $20,000 insert to survive about 100 pulses. The $8 million outsert should last about 10,000 pulses. Each time the magnet pulses it bends the copper and silver wires, creating tiny cracks in the metal. The cracks in the copper run into the silver wires, which stops the cracks from spreading.

"It's like reinforced concrete," said Boebinger.

The copper acts like like the concrete, strong and tough. The silver acts like the steel rebars running through the concrete, providing flexibility.