Delayed X- and Gamma-Ray Line Emission Delayed X- and Gamma-Ray Line Emission from Solar Flare Radioactivityfrom Solar Flare Radioactivity

V. Tatischeff, B. Kozlovsky, J. Kiener and R. J. Murphy ApJS, submitted

Proposed by Ramaty & Mandzhavidze (2000, IAU Symp.) size and development of the radioactive patch mixing and transport processes in the solar atmosphere the most promising delayed line is at 847 keV from 56Co decay

Selection Selection of the of the

RadioisotopRadioisotopeses

•10 min <T1/2 < 77

days

•21 +-emitters

(KLR87 + KMS04) + 7Be, 24Na, 56Mn, 58Com

• Updated cross

sections for the

production of 34Clm, 52Mng, 52Mnm, 55Co, 56Co, 57Ni, 58Cog, 60Cu and 61Cu by p,

and 3He reactions

Radioisotope Production Cross Radioisotope Production Cross SectionsSections

TALYS calculationsData: Michel et al. (1997)

x10-2

x10-4

x10-6

Experimental reaction data from EXFOR http://www.nndc.bnl.gov/exfor/

+ Theoretical estimates from EMPIRE-II (version 2.19), TALYS (version 0.64), and the "Silberberg & Tsao" code above ~250 MeV (cosmic-ray physics)

Radioisotope Production YieldsRadioisotope Production Yields Thick target interaction model with nuclear destruction and

catastrophic energy loss (e. g. pion production) of the fast ions (interactions between fast and ambient heavy ions are negligible)

Power law source spectrum up to 1 GeV/nucleon, with s=3.5, 2 and 5

Impulsive-flare composition from SEP, with /p=0.5 and 3He/=0.5

Delayed line Delayed line emission emission 30 min30 min after the end of after the end of

the flarethe flare

Unexpected strong lines at 1434 keV from 52Mnm, 1332 and 1792 keV from 60Cu, 6.92 (Co K) from 58Com (Ex=25 keV)

+ 57Ni, 2127 keV from 34Clm...

* Normalized to a fluence of 300 cm-2 emitted in the sum of the 4.4 and 6.1 MeV prompt narrow lines (2003 Oct. 28 flare)

*

The experimental The experimental proofproof

Delayed line Delayed line emission emission 3 h3 h after after

the flarethe flare

The strongest line after that at 511 keV can be the neutral Co K line

Photoelectric attenuation: at solar depths of 10-3–10-1 g cm-

2 (low chromosphere), the optical depths of 6.92 keV X-rays are ~ 10-3–10-1

X-ray imaging of the radioactive patch ?

* Normalized to a fluence of 300 cm-2 emitted in the sum of the 4.4 and 6.1 MeV prompt narrow lines (2003 Oct. 28 flare)

*

Delayed line Delayed line emission emission 3 days3 days

after the flareafter the flare

*

Time dependence Time dependence of the 511 keV line of the 511 keV line

From ~1 to ~14 hours, the main source of the positrons is 18F, which can be mainly produced by 16O(3He,p)18F

Measurement of the 511 keV decay curve can provide the accelerated 3He abundance

The influence of the The influence of the accelerated ion compositionaccelerated ion composition

Reames (1995)

3He/4He

H/4

He

Reames et al. (1994)

?

SEP composition for fast C and heavier elements relative to -particles, but with /p=0.5 ( – line in -ray flares, SM97...)

Strong enhancement of the fast heavy elements, with e.g. AFe/Ap=137 nFe/nH

The delayed lines will measure this enrichment

The Gamma-Ray ImagerThe Gamma-Ray Imager… an artist’s Cosmic

Vision

From J. Knödlseder, ESLAB Symposium 2005