Solar - Nuclear Fusion

Question 1

Where does solar energy come from?

Answer 1

Nuclear Fusion

Question 2

Nuclear Fusion

Answer 2

Fusion of hydrogen to helium

Question 3

Sun composition

Answer 3

74% hydrogen, 24% helium

Question 4

First step of nuclear fusion

Answer 4

Fusion of two protons by weak interactions, forming deuterium, releasing an electron neutrino, a positron and 1.43mev of energy

Question 5

Coulomb Repulsion Barrier

Answer 5

An energy barrier due to electrostatic interactions that tow nuclei must overcome to get close enough for nuclear reaction

Question 6

What is thermal barrier of coloumb?

Answer 6

0.2MeV and 1.4x10^9K, 100 times greater than core of sun

Question 7

What two processes allow nuclear fusion?

Answer 7

Quantum Tunneling
Boltzmann Distribution

Question 8

Centre of Mass Frame

Answer 8

An inertial frame where centre of mass remains at the origin

Question 9

What is fusion rate a product of?

Answer 9

Probability of finding two particles with energy E in their centre of mass frame
Probability these two particles get close to interact, depending on quantum tunneling
Reaction rate factor, describing likelihood of a fusion event

Question 10

Quantum Tunneling

Answer 10

Passage of minute particles through seemingly impassable force barriers

Question 11

Boltzmann Distribution

Answer 11

Describes probability of finding a particle in a certain state, in a gas at a particular temperature

Question 12

Maxwell Boltzmann Distribution

Answer 12

Concerns distribution of amount of energy between identifcal but distinguishable particles.

Question 13

What does MBD suggest?

Answer 13

Hot gases have assumed constant energies as energy is realtively closs regardless

Question 14

Prediction of MBD

Answer 14

There are many molecules with energies higher than the average

Question 15

How many MBD particles are there in one mole?

Answer 15

10^8 with 10 times mean energy, not enough to overcome the barrier

Question 16

What determines barrier penetration factor?

Answer 16

Resilience of the barrier and energy of the particle

Question 17

What is probability of tunneling described by?

Answer 17

Gammow factor

Question 18

Gammow factor

Answer 18

This is a probability of the boltzmann factor and the barrier penetration factor

Question 19

When is fusion possible?

Answer 19

When a gamow window opens

Question 20

When does tunneling probabiltiy become significant?

Answer 20

When boltzmann distribution is below coloumb barrier energy of 0.2MeV

Question 21

What are the reactions of Nuclear Fusion?

Answer 21

Two deuterium merge forming helium, or interact with protons forming He-3, where two He-3 can fuse to make Be-6, which can break forming He-4 and two protons

Question 22

How are photons produced?

Answer 22

Interplay of nuclear force and coulomb force, or positron and electron annihiliation.