Superconducting coil device with continuous current switch and method for switching
A coil device with at least one electrical coil winding with superconducting conductor material and a vacuum container is described in which the vacuum container surrounds the coil winding. The coil winding is part of a self-contained circuit for the formation of a continuous current. The closed circuit has a switchable conductor section, the conductor of which can be switched between a superconducting state and a normally conducting state by a magnetic device. The magnetic device has an internal part arranged inside the vacuum container and an external part arranged outside the vacuum container.
1. A coil device, comprising:
a self-contained circuit for the formation of a continuous current including at least one electrical coil winding with superconducting conductor material, and a switchable conductor section having a conductor switchable between a superconducting state and a normally conducting state;
a vacuum container surrounding the at least one electrical coil winding; and
a magnetic device, switching the switchable conductor section of the self-contained circuit between the superconducting state and the normally conducting state, the magnetic device having an internal part arranged inside the vacuum container and an external part arranged outside the vacuum container;
wherein the internal part of the magnetic device has at least one internal flux guiding element, and wherein the external part of the magnetic device has at least one external flux guiding element and at least one magnet.
2. The coil device as claimed in claim 1 , wherein the at least one magnet includes a permanent magnet.
3. The coil device as claimed in claim 1 , wherein the at least one magnet includes an electromagnet.
4. The coil device as claimed in claim 1 , wherein the internal part of the magnetic device is fixed in the vacuum container.
5. The coil device as claimed in claim 1 , wherein the vacuum container has an external wall of a non-magnetic material at least adjacent the magnetic device.
6. The coil device as claimed in claim 1 , wherein the superconducting conductor material includes a superconducting coated conductor.
7. The coil device as claimed in claim 6 , wherein the magnetic device has a directional component substantially perpendicular to a plane of the superconducting coated conductor in a region including the switchable conductor section where a magnetic field is formed by the magnetic device.
8. The coil device as claimed in claim 7 , wherein the superconducting coated conductor is a bifurcated coated conductor with a doubly connected topology.
9. The coil device as claimed in claim 6 , wherein the superconducting coated conductor is a bifurcated coated conductor with a doubly connected topology.
10. The coil device as claimed in claim 1 , wherein the superconducting conductor material continuously extends over all of the closed circuit.
11. The coil device as claimed in claim 1 , wherein the switchable conductor section adjoins a radially external region of the coil winding.
12. A method for switching a conductor section of a coil device between a superconducting state and a normally conducting state, the coil device including at least one electrical coil winding with superconducting conductor material and a vacuum container surrounding the coil winding, the coil winding being part of a self-contained circuit for formation of a continuous current, the method comprising:
at least one of increasing and lowering of a magnetic field generated by a magnetic device in a region including the conductor section;
the magnetic device having an internal part arranged inside the vacuum container and an external part arranged outside the vacuum container;
wherein the internal part of the magnetic device has at least one internal flux guiding element, and wherein the external part of the magnetic device has at least one external flux guiding element and at least one magnet.
13. The method as claimed in claim 12 , wherein the magnetic field in the external part of the magnetic device is generated by a permanent magnet or an electromagnet.
14. The method as claimed in claim 12 , wherein application of the magnetic field initially results in a reduction of a critical current density in the superconducting state of the conductor section and subsequently results in supply of a current from an external feed circuit for achievement of the normally conducting state of the conductor section.
15. The method as claimed in claim 14 , wherein switching of the conductor section is achieved at an operating temperature of between 15 K and 77 K.
16. The method as claimed in claim 13 , wherein switching of the conductor section is achieved at an operating temperature of between 15 K and 77 K.
17. The method as claimed in claim 12 , wherein switching of the conductor section is achieved at an operating temperature of between 15 K and 77 K.