An interview with Roald Sagdeev: his story of plasma physics in Russia, 1956–1988 Roald Z. Sagdeev and Patrick H. Diamond Eur. Phys. J. H, 43 4-5 (2018) 355-396 Published online: 23 October 2018 DOI: 10.1140/epjh/e2018-90042-3