02-01-2013, 02:27 PM
SUPERCONDUCTING MAGNETIC LEVITATION
SUPERCONDUCTING.pptx (Size: 3.57 MB / Downloads: 63)
PRINCIPLE OF LEVITATION
Superconductors are materials exhibiting two basic features:
(i) zero resistivity
(ii) Ideal diamagnetism - i.e. they expel magnetic field from their volume.
A permanent magnet together in combination with a superconductor forms a very effective and stable configuration.
After cooling the superconductor below its critical temperature, tiny channels are formed in the superconductor, called vortices.
The external magnetic field is thus "frozen" in the superconductor in the form of vortices.
The superconductor opposes to any change of the original configuration of the external magnetic field, both in magnitude and direction.
An effective magnetic trap is thus formed that keeps the permanent magnet in its original position.).
VORTICES
In a type 2 superconductor, vortices are oriented parallel to the external magnetic field.
Each vortex captures and takes inside the superconductor B “single” magnetic field line.
With an increase in the strength of the external magnetic field the number of vortices increases and the distance between them becomes smaller.