Confirmation%20of%20extended%20annihilation-line%20emission%20in%202005%20January%2020%20flare:%20Earth%20occultation.

1
(No Transcript)
2
Confirmation of extended annihilation-line
emission in 2005 January 20 flare Earth
occultation.

Day
Night
3
(No Transcript)
4
(No Transcript)
5
Evidence for hard particle spectrum in the
01/20/05 flare
Hard (pion?) Component
Spectrum dominated by bremsstrahlung (dots), 511
keV and n-capture (2223 keV lines and hard
component. Narrow lines (solid) not clearly
detected also suggesting hard spectrum.
6
(No Transcript)
7
Calculated gamma-ray spectra vs
flare-accelerated particle power-law index.
Nuclear continuum masks narrow lines for hard
spectra.
8
Spectrum after hard component subtracted
9
Extended 511 keV flux comes from high-energy
solar photons interacting in the spacecraft. Are
these from solar pion radiation? High-energy
appears to contain particles gt0715 and possibly
neutrons gt0655.
10
Counts gt20 MeV shows early peak coincident with
sharp peak at 511 keV (likely to be high-energy
solar photons causing instrumental line). Later
peaks suggest neutron detection and strong
particle emission (lat gt 30o). Abrupt drop in
rate at Earth occultation consistent with
high-energy solar photons.
11
(No Transcript)
12
511 keV line is broad early in flare and is
dominated by the delayed beta-decay produced
solar annihilation line. Late in the flare line
is narrower, consistent with instrumental origin
associated with high-energy solar photon impact
on the spacecraft.
13
(No Transcript)
14
(No Transcript)
15
1/20/2005
Spectra from three RHESSI flares revealing
differing amounts of pion radiation inferred from
9-16 MeV emission. Coronas confirms pion emission
in the October 28 and January 20 flares. No
evidence for pion emission in November 2 flare
10/28/2003
11/02/2003