... publish R. Atkinson and F.G. Houtermans in 1929 a paper in the Zeitschrift für Physik which brings for the first time together Rutherford's model of the atom and Einstein's nowadays most famous formula, in order to hypothesize the mass defect in the fusion of light atomic nuclei as the energy source of stars.

The same year, L. Tonks and I. Langmuir introduce the term "plasma" together with their theory of electric arcs (the flash, e.g.).

Houtermans (Figure) emigrates in 1933 to London, leaves for the Soviet Union in 1935 (where he is told to have been engaged in fusion experiments, too), falls in 1937 into a stalinistic purge, survives two years of detention with the help of fellow-prisoners, becomes extradited in 1939 to the Gestapo, is set free in 1940 upon M.v. Laue's intervention and becomes employed, with help of the latter, at the Zeuthen institute just founded of M.v. Ardenne (nowadays DESY Zeuthen) - where he writes a laboratory report in 1941, entitled

"On the question of triggering a nuclear chain reaction".

He cares for leaking out information towards Princeton, which don't alert anyone there, however, and falls lately into the unjustified suspicion of collaboration with the Nazis.

Anticipation of the (CNO) fusion cycle found in 1938 independently then by H. Bethe and C.F.v. Weizsäcker - the one that takes place in stars hotter than the Sun - makes him a pioneer of fusion research.