More phenomena difficult to observe

1. More phenomena difficult to observe A MacKinnon

2. More phenomena difficult to observe synchrotron radiation of positrons: sub-mm observations? inner bremsstrahlung of secondary neutrons

3. Positron energy distribution from + decay really, this is what is injected into the source by colliding p’s, ’s =2, Tmax = 3 GeV/nucl

4. Effective distribution in thick target source dE/dt : collisions (logarithmic energy dependence – constant!) synchrotron (2) bremsstrahlung ( - above 100 MeV)

5. Cumulative e+ distribution – ‘mean distribution’ in source divide these by dE/dt

6. Synchrotron spectrum – monoenergetic e c = 4.3×106 B 2 sin

7. Synchrotron spectrum

8. Rough estimate • 1032 protons above 300 MeV • × 10-2 e+ per proton • 4×10-22 1000erg.s-1 .Hz-1 × 10-2 s lifetime spread out over e.g. 100 s and divided by 4  AU2 ~ 10-20 erg.cm-2.s-1 .Hz-1 = 10-23 W.m-2.Hz-1 = 10-1 s.f.u. TOO SMALL

9. Inner Bremsstrahlung spectrum Knipp and Uhlenbeck (1936); Bloch (1936); Petrosian and Ramaty (1972)

10. Angular distribution of IBXR’s r = solar distance z = distance from Earth distances in AU

11. Briefly: • X-ray flux integrates over all neutron energies present along the line of sight • looking further from the Sun samples more energetic neutrons because lower energy ones decay • Approximately, the distribution of X-ray flux with angle is the Laplace transform of the neutron energy distribution at the Sun • invert integral equation to deduce neutron energy distribution F(E)

12. Example

13. Sun’s X-ray halo

14. Seckel et al. (1992) • modelled turbulent transport of cosmic rays in inner heliosphere + interaction with small-scale magnetic fields near solar surface (lots of assumptions!) • predicted 2.3×10-8 neutrons.cm-2.s-1 above 100 MeV at 1 AU • assume F(E)(E+10)- at the Sun and normalise to this prediction •  IB flux at <1% of cosmic XRB in 2 – 10 keV range

15. After flares? • look near large, limb flares……..