Bitter electromagnet
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A Bitter electromagnet or Bitter solenoid is a type of electromagnet made of metal plates and insulating spacers stacked in a helical configuration, rather than coils of wire. This design was created and built in 1933 by Francis Bitter. In his honor the plates are known as Bitter plates.
Bitter electromagnets are used to produce extremely strong magnetic fields (up to 60 teslas as of 2006). The stacked plate design is mechanically very sturdy, to withstand the outward pressure produced by Lorentz forces, which increase as the square of the magnetic field strength. Additionally, water circulates through holes in the plates as a coolant, as resistive heating also increases as the square of the magnetic field strength.
Despite the drawback of resistive heating, Bitter electromagnets are used where extremely strong fields are required because superconducting electromagnets cannot operate above the field strength at which the magnet materials cease to be superconducting (typically on the order of 10 to 20 teslas, due to flux creep, though theoretical limits are higher).
[edit] External links
- National High Magnetic Field Laboratory Magnet Projects Page at Florida State University
- Magnets at Nijmegen High Field Magnet Laboratory
- Levitating frog and a ball of water inside a Bitter solenoid at the High Field Magnet Laboratory
- Diagrams and description of the Bitter solenoid used in the frog levitation demonstration
