noun
thermonuclear fusion
Technical term in physics for the fusion of atomic nuclei at extremely high temperatures, as in stars or hydrogen bombs.
太陽のエネルギーは熱核融合反応によって生み出されている。
The sun's energy is produced by thermonuclear fusion reactions.
核融合 is the general term for nuclear fusion, while 熱核融合 specifically refers to fusion triggered by high temperatures.
Compound of 熱 (netsu, 'heat') + 核融合 (kakuyūgō, 'nuclear fusion').