11: COSMIC RAY HEAVIES

Question 1

Define spallation.

Answer 1

CR heavies striking ISM can fragment into lighter elements.

Question 2

1. When are energy losses important for heavies?
2. Why is the CR spectrum unmeasurable?
3. What happens to energy term?

Answer 2

1) For less than or equal to 200 MeV
2) Solar modulation
3) Ignore the energy-loss term.

Question 3

What causes diffusion?

Answer 3

Nuclei scatter like gas particles.

Question 4

Leaky Box Model:
1. What is assumed about CR sources?
2. What is assumed about the Galaxy?
3. What does diffusion produce and what does this cause?

Answer 4

1. Uniformly distributed in space
2. It’s a finite confinement volume
3. A distribution of path lengths
4. CRs escape from the Galaxy

Question 5

What is assumed in the leaky-box model?

Answer 5

1. Assume steady state: ∂nj/∂t=0
2. Allow new production: Qj not equal to 0
3. Allow diffusion with leakage: D∇2n 6= 0

Question 6

Which elements are products from a source and not spallation?

Answer 6

Fe-56, C-12, O-16, Ne-20, Mg-24, Si-28

Question 7

What are Li, Be, and B?

Answer 7

Spallation secondaries.

Question 8

1. What is the energy spectra of spallation secondaries compared to primaries?
2. Why?
3. What happens to spallation as a result?

Answer 8

1. Steeper energy spectra.
2. Higher-energy CRs escape more easily from the Galaxy
3. Spallation is reduced.

Question 9

Which CRs have a radius of curvature in the Galaxy B field less than or equal to 1kpc?

Answer 9

All but the highest-energy ones.