Proton-Proton FusionThis is the nuclear fusion process which fuels the Sun and other stars which have core temperatures less than 15 million Kelvin. A reaction cycle yields about 25 MeV of energy.
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | ||
|
Go Back |
Proton-Proton CycleThe fusion of hydrogen in lower temperature stars like our Sun involve the following reactions yielding positrons, neutrinos, and gamma rays.
which can be followed by either The latter of these reactions is part of what is usually called the proton-proton cycle, which yields about 25 MeV and can be combined to the form
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | |||
|
Go Back |
Step 1. Proton Fusion
With the development of quantum mechanics, it was realized that on this scale the protons must be considered to have wave properties and that there was the possibility of tunneling through the coulomb barrier.
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | ||||
|
Go Back |
Eddington and his fusion criticsArthur Eddington thought that nuclear processes must be involved to account for the radiant energy of the sun, but was criticized because the temperature was seen to be not hot enough when considered by classical physics alone. His tongue-in-cheek reply to his critics: "I am aware that many critics consider the stars are not hot enough. The critics lay themselves open to an obvious retort; we tell them to go and find a hotter place."
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | ||
|
Go Back |
Step 2. Deuterium formation
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | ||||||
|
Go Back |
Step 3. Deuterium-proton fusion
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | |||
|
Go Back |
Step 4. Helium-3 fusion
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | |||
|
Go Back |
Step 5. Alpha particle formation
|
Index Carroll & Ostlie Ch 10.3 Krane, Intro. Nuclear Physics Ch 14.3 | |||
|
Go Back |