The 35 Tesla Resistive Magnet

Vital Statistics Strength 35 tesla Type Resistive Bore size 32 mm (~1.25 inches) Online since December 2005 Cost $0.5 million Weight 2,500 kg (2.75 tons) Height 1.52 meters (~5 feet) Water used per second 139 liters (~37 gallons) Power required 19.6 MW

Overview

This is one of world's most powerful resistive magnets. Resistive magnets are also called “powered” or “Bitter” magnets. Unlike superconducting magnets, which can be unplugged after first being powered up, this magnet needs LOTS of electricity to generate its high magnetic field.

Mag Lab engineer Jack Toth examines a Bitter plate.

Like the other resistive magnets here, the 35 tesla is constructed of hundreds of flat, round sheets of metal stacked one on top of the other. Made of high-strength copper alloys, these plates can withstand both the pressure resulting from high magnetic fields and the heat resulting from the 19.6 megawatts of electrical power that make it run. These plates are called Florida Bitter plates – “Bitter” after the fellow who invented them in 1936 (Francis Bitter), and “Florida” in honor of the Mag Lab scientists who greatly improved on Bitter’s design, which enabled the creation of more powerful magnets like the 35 tesla. The magnetic field is concentrated in the big hole in the middle of the plates; that’s where researchers put their experiments. The smaller holes allow the cold water that keeps the magnet from overheating to run through – at a speed of 45 miles per hour.

This magnet is generally used for condensed matter physics (basic materials science).

Links

• What's a Resistive Magnet?
  As defined by a Mag Lab expert (audio file).
• What's a Bitter Plate?
  As defined by a Mag Lab expert (audio file).
• Magnets from Mini to Mighty
  If your knowledge of magnets ends with posting a to-do list on the fridge, add this to the list: Learn more about magnets!
• Making Resistive Magnets (article)
  Building the world's best resistive magnets requires clever engineering, top-notch science, superior materials and an obsession with quality control.
• Making Resistive Magnets (audio slideshow)
  Building the world's best resistive magnets requires clever engineering, top-notch science, superior materials and an obsession with quality control.
• Team Tesla: How We Keep the World’s Most Powerful Magnets in Shape
  Our magnets require vast amounts of electricity and water. See how our operations work.
• Users Hub: The 35 Tesla Magnet
  Details for scientists.