PHYS 7 Lecture Notes - Nuclear Fusion, Nuclear Fission, Photosphere
Document Summary
Nuclear fission splits a nucleus into smaller nuclei, while nuclear fusion combines smaller nuclei into a larger nucleus. Nuclear fusion occurs in core, where energy from process makes it"s way to photosphere, the outer layer of the sun. In the sun, four hydrogen nuclei (protons) fuse into one helium-4 nucleus by way of the proton-proton chain. Gamma rays and subatomic particles known as neutrinos and positrons carry off the energy released in the reaction. Steps: 1. two protons fuse to make a deuterium nucleus (1 proton and 1 neutron). This step occurs twice in the overall reaction: the deuterium nucleus and a proton fuse to make a nucleus of helium-3 (2 protons, 1 neutron). This step also occurs twice: two helium-3 nuclei fuse to form helium-4 (2 protons, 2 neutrons), releasing two excess protons in the process. Radiative diffusion: the slow outward migration of photons.
