Introduction

Superconductivity is one of the most important discoveries in physics in the twentieth century and has just celebrated its 100th birthday. Investigating the origins of the universe in particle accelerators or having detailed images of the human body with MRI would be impossible without employing technology based on superconductors. The near future will see superconductors enter our everyday life even more deeply, in the form of cables powering our cities, fault current limiters protecting our electric grids, and super-fast levitating trains reducing dramatically travel times.

Course goals

After attending this course, the students will have:

• Received an introduction to superconductivity, with an overview of its main features and of the theories developed to explain it 
• Learned about superconducting materials and their properties, especially those currently employed in energy applications (niobium-based superconductors, oxocuprates, MgB2) and promising recently discovered ones (pnictides)
• Learned about superconducting materials and their properties, especially those currently employed in energy applications (niobium-based superconductors, oxocuprates, MgB2) and promising recently discovered ones (pnictides)

Content

1. Introduction: Presentation of the course. Goals, structure, schedule, practical details. 
2. Physics of superconductivity (I): Discovery of superconductivity. Meissner state. Superconductors vs. perfect conductors. Theories of superconductivity: London, Ginzburg-Landau, BCS. 
3. Physics of superconductivity (II): Phase diagrams, mixed state, type-I and type-II superconductors, flux flow and flux creep. 
4. Materials (I): Low-temperature superconductors (NbTi, Nb3Sn). Wire manufacturing, physical properties (microstructure, macroscopic characterization). 
5. Materials (II): High-temperature superconductors (BSCCO, YBCO). Bulk, tapes and wires. Manufacturing, physical properties (microstructure, macroscopic characterization). 
6. Materials (III): Magnesium diboride (MgB2) and pnictides. Manufacturing, physical properties (microstructure, macroscopic characterization). 
7. Stability: Disturbance spectrum. Degradation and training. Requirements for stability. Heat balance. Stability criteria. 
8. AC losses: Dissipative phenomena in superconductors. Different loss contributions (hysteretic, eddy current, coupling losses). Techniques to measure losses. 
9. Numerical modeling: Analytical and numerical models. Comparison with experiments for single tapes and complex devices. Facultative practical lecture: simulation of superconductors
10. Energy applications (I): Overview of energy applications of superconductors: NMR magnets, fusion magnets, cables. 
11. Energy applications (II): Overview of energy applications of superconductors: fault current limiters, motors, transformers, SMES. 
12. Excursion: Lab tour Visit of several experimental facilities of the Institute for Technical Physics – KIT Campus N or of the Bruker company (manufacturer of magnets for MRI).

Attendance

16.5 hours + excursion
Self-study: 100 hours

Media

Blackboard, PowerPoint slides, script written by the teacher (100+ pages)

Literature

Various. It will be provided on a lecture-by-lecture basis.