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,
Heike ondo drums and the taru barrel in his or her ensemble, in intricate drumming techniques. Heike Ondo is accompanied by a kind of shamisen called the Heike Shamisen, which has a shorter neck than most shamisens in Japan, and thus, a higher range. The narrative is quite long and is rarely ever sung in its entirety; key excerpts are chosen for shorter performances. The song is sung by a main singer accompanied by a group of singers who know when to call out the kakegoe (see below). The dance that accompanies Heike Ondo is called Heike Odori (平家踊り). It is simple