Working Group 2 - Ion acceleration and interactions.
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Working Group 2 - Ion acceleration and interactions
2005 January 20 Flare High-energy emission delayed and has an extended tail. Particles reach Earth ~3 min after high-energy photons
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 >07:15 and possibly neutrons >06:55.
Counts >20 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/particle detection and strong particle emission (lat > 30 o ). Abrupt drop in rate at Earth occultation consistent with high-energy solar photons.
TRACE 1600A at 06:52:30 UT 2005 Jan. 20 250 – 500 keV 30, 50, 70, 90% contours 2215-2231 keV centroid 1- error circle
Imaged / Spectral 2.223 MeV count ratios are consistent with 1. Ions interact in a compact region associated with footpoints. Not a from a broad region as expected from CME-related shocks. Ions are flare-accelerated Not all Jan. 20 511 keV flare counts are imaged--> consistent with solar 511 keV photons and instrumental photons from interactions of high-energy (>10 MeV) photons. May be possible to image >10 MeV photons in 2005 January 20 flare.
RHESSI 2003 October 28 Time Histories Fit to 511 keV line flux indicates a hard spectrum, including contribution from pion decay 3 continuum just after impulsive peak also suggests positrons from pion decay RHESSI observed emission >20 MeV. SONG (CORONAS-F) observed >60 MeV gamma rays in peak consistent with neutron pion decay. Striking change in 511 keV line width after 11:16; nothing exceptional occurring in fluxes
Striking correlation of gamma-ray line and bremsstrahlung fluences in flares detected >300 keV RHESSI SMM After selection cuts Direct proportionality
Correlation coefficients between X-ray flux at 150 keV and gamma ray flux during the impulsive part of the flare Origin of the delay: acceleration or transport effects? Share et al, 2003 Delay of 12 s between hard X-ray flux at 150 keV and gamma ray lines The 23 July event Time delay analysisModelConclusionsIntroductionTime profile analysis Time delay between hard X-ray and gamma ray lines observed by RHESSI during the 23 July event
-ray flux correctly reproduced for a constant spectral index but the injection amplitude are different Best fit: - n=1.10 10 cm -3 - 2 /L=10 -6 km -1 The 23 July eventTime delay analysisModelConclusionsIntroduction Time profile analysis Time delay between hard X-ray and gamma ray lines observed by RHESSI during the 23 July event Gamma-ray lines flux 2 nd step =-3.75 (Lin et al, 2003) We change the ratio q 0 /q i for each injection, i.e. the number of electrons and ions accelerated in each injection is not necessarily the same