Superconducting magnet issues "shaken" out of them, until they are eventually able to operate reliably at their full planned current without experiencing quenches. Although the idea of making electromagnets with superconducting wire was proposed by Heike Kamerlingh Onnes shortly after he discovered superconductivity in 1911, a practical superconducting electromagnet had to await the discovery of superconducting materials that could support large critical supercurrent densities in high magnetic fields. The first successful superconducting magnet was built by G.B. Yntema in 1955 using niobium wire and achieved a field of 0.7 T at 4.2 K. Then, in 1961, J.E. Kunzler, E. Buehler, F.S.L. Hsu,
Groningen back to 1614. After the University of Leiden, it is the second oldest Dutch university. The university educated the first female student, Aletta Jacobs, the first Dutch national astronaut, Wubbo Ockels, the first president of the European Central Bank, Wim Duisenberg and two Nobel prize winners, Heike Kamerlingh Onnes and Ben Feringa. 200,000 people were either students, teachers or researchers at the university. Groningen has the highest percentage of students by total population, approximately 25 percent. The city council has 39 members. With 9 seats, the social-liberal D66 is the largest party on the council. The social-democratic PvdA has 6