“At the age of between 12 and 15 I was drawing; I was making plans of fusion devices.” David Fischer remembers growing up in Vienna, Austria, imagining how best to cool the furnace used to contain the hot soup of ions known as plasma in a fusion device called a tokamak. With plasma hotter than the core of the sun being generated in a donut-shaped vacuum chamber just a meter away from these magnets, what temperature ranges might be possible with different coolants, he wondered. “I was drawing these plans…
