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Solar flare observations with INTEGRAL/SPI. (M. Gros, J. Kiener, V. Tatischeff et al.). Nuclear g -rays. e -. p, a. Hard X-rays. Neutrons. CORONA. TRACE & RHESSI, 28-Oct-2003. 2.22 MeV g -ray line. CHROMOSPHERE. n. PHOTOSPHERE. H. 12 C*. 12 C. p.

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solar flare observations with integral spi
Solar flare observations with INTEGRAL/SPI

(M. Gros, J. Kiener, V. Tatischeff et al.)

Nuclear g-rays

e-

p, a...

Hard X-rays

Neutrons

CORONA

TRACE & RHESSI, 28-Oct-2003

2.22 MeV g-ray line

CHROMOSPHERE

n

PHOTOSPHERE

H

12C*

12C

p

  • Nuclear de-excitation lines:

hn

IEEC, Barcelona, September 23, 2004

the integral satellite

Masks

BGO shield

ISGRI (CdTe)

PICSIT (CsI)

Ge detector matrix

The INTEGRAL satellite
  • Scientific objectives: AGN, g-ray bursts, compact objects, novae, SNe, interstellar g-ray emissions...
  • Launched (Proton) on 17 Oct 2002

IEEC, Barcelona, September 23, 2004

interest of spi for solar flare physics
Interest of SPI for solar flare physics
  • Compact array of 19 hexagonal Ge detectors (Stot=500 cm2): good efficiency at high energy (compared to RHESSI) using "multiple events"
  • Anti-Coincidence veto System (ACS) of 91 BGO scintillator crystals: Spro~6000–9000 cm2

IEEC, Barcelona, September 23, 2004

spi observations of the 2003 oct 28 solar flare x17 2

Masks

BGO shield

32 °

ISGRI

PICSIT

Ge detector matrix

BGO shield

SPI observations of the 2003 Oct 28 solar flare (X17.2)
  • During INTEGRAL observation of IC443 (rev 127; PI: A. Bykov)
  • Simulated response function for the satellite configuration during the flare: in progress(Weidenspointner et al.)
  • All results are preliminary

IEEC, Barcelona, September 23, 2004

measured spectra and time history
Measured spectra and time history

pair prod.

mostly instrumental

  • With all types of Ge events (including multiples 2-5)

IEEC, Barcelona, September 23, 2004

4 44 and 6 13 mev line characteristics

Compton

4.44 and 6.13 MeV line characteristics

+ 0.23

- 0.22

+ 0.95

- 0.65

+ 0.24

- 0.29

+ 1.11

- 0.83

  • RHESSI results are for the 23 July, 2002 X4.8 flare (73° helio. angle)-Smith et al. 2003

IEEC, Barcelona, September 23, 2004

slide7

common best fit

12C best fit

95.4 % C.L.

90 % C.L.

68.3 % C.L.

common best fit

16O best fit

4.44 and 6.13 MeV line shape calculations

  • Detailed model based on laboratory data
  • Sensitive to the angular distributionof theacceleratedparticlesandthea/pratio
  • Best fit results:
  • 12C only : a/p = 0.00DQ = 20°
  • 16O only : a/p = 0.09 DQ = 34°
  • 12C +16O : a/p = 0.03 DQ = 29°

IEEC, Barcelona, September 23, 2004

the 6 92 and 7 12 mev lines of 16 o
The 6.92 and 7.12 MeV lines of 16O*
  • Fit with a fixed line shape: same relative redshift and FWHM as for the 6.13 MeV line
  • The two 16O* lines at ~7 MeV are resolved for the first time
  • From a simplified model of solar g-ray absorption:

IEEC, Barcelona, September 23, 2004

gamma ray line ratios
Gamma-ray line ratios
  • Fast ion composition: Solar Energetic Particles (SEP) from impulsive flares
  • Fast ion energy spectrum: dN/dE  E-S
  • Nuclear de-excitation lines (thick target production model) compared to 2.22 MeV line production (Hua et al. 2002)  DS

?

Smin for a/p=0.1

Smax for a/p=0.1

IEEC, Barcelona, September 23, 2004

with a stochastic acceleration spectrum
With a stochastic acceleration spectrum

The source spectrum should be a modified Bessel function rather than a power law (e.g. Forman et al. 1986).

 no improvement for C/O

a: acceleration efficiency T: escape time from the acceleration region

?

IEEC, Barcelona, September 23, 2004

with smm and osse data
With SMM and OSSE data
  • 9 SMM flares with strong (and complete) g-ray line emission (SM95)
  • OSSE: 1991 June 4 flare (Murphy et al. 1997)
  • RHESSI results not yet taken into account

DS determination for the 1989 Nov 15 flare

Correction for heliocentric angle

?

IEEC, Barcelona, September 23, 2004

the 12 c 16 o line ratio problem
The 12C/16O line ratio problem

from Ramaty et al.

  • Calculated F(4.44)/F(6.13) overestimates by a factor of ~1.5 the average line ratio obtained from SMM, OSSE and SPI data.
  • Origin of the problem: - the interaction model ? - the cross sections ? - the abundances of 12C and 16O in the ambient medium (coronal, from gradual event SEP) ?
  • comparison with the 2 other significant lines detected with SMM and OSSE: at 1.37 (24Mg*) and 1.63 MeV (20Ne*)

IEEC, Barcelona, September 23, 2004

cross sections 1
Cross sections (1)

Mainly from KMR02 (ApJ Suppl), the figures.

  • 4.44 MeV lineS=3S=4.5

a: 12C(p,p’)12C*47.4%43.1%

b: 14N(p,x)12C* () 1.6% 0.2%

c: 16O(p,x)12C*35.7%9.5%

d: 12C(,’)12C*8.7%39.3%

e: 14N(,x)12C* () 0.4% 0.3%

f: 16O(,x)12C*6.3%7.5%

A(b,c)D: cross section measured by the g-ray method (10–20% uncertainties)

(with a/p=0.1)

(): Cross sections overestimated in KMR02 ; calculated with EMPIRE-II (nuclear statistical model)

IEEC, Barcelona, September 23, 2004

cross sections 2
Cross sections (2)
  • 6.13 MeV line 6.129 MeV (16O*) + 6.175 MeV (15O*),

but not the 6.322 MeV line (15N*), see Mandzhavidze et al. (1999).

S=3S=4.5

a: 16O(p,p’)16O*67.0%42.7%

b: 20Ne(p,x)16O* 6.0% 1.6%

c: 16O(p,x)15O* 11.0% 0.5%

d: 16O(,’)16O*15.2%54.4%

e: 20Ne(,x)16O* () 0.6% 0.8%

f: 16O(,x)15O* <0.1% <0.1%

(): Cross section not considered in KMR02, calculated with EMPIRE-II

IEEC, Barcelona, September 23, 2004

cross sections 3
Cross sections (3)
  • 7 MeV lines 6.92 MeV + 7.12 MeV (16O*)

S=3S=4.5

a: 16O(p,p’)16O*6.9278.0%40.0%

c: 16O(,’)16O*6.9222.0%60.0%

b: 16O(p,p’)16O*7.1287.1%52.3%

d: 16O(,’)16O*7.1212.9%47.7%

  • Minor contributions (neglected) from 20Ne spallation (EMPIRE-II)

IEEC, Barcelona, September 23, 2004

cross sections 4
Cross sections (4)
  • 1.63 MeV line 1.634 MeV (20Ne*) + 1.636 MeV (23Na*) + 1.635 MeV (14N*)

S=3S=4.5

a: 20Ne(p,p’)20Ne*55.1%62.1%

b: 24Mg(p,x)20Ne*,23Na* 20.5% 4.1%

c: 28Si(p,x)20Ne* 5.3% 0.5%

d: 20Ne(,’)20Ne*7.0%27.1%

e: 24Mg(a,x)20Ne*,23Na* 2.5% 1.3%

a’: 14N(p,p’)14N* 4.1%2.9%

b’: 16O(p,x)14N* 4.9% 0.3%

c’: 14N(,’)14N*0.6%1.8%

IEEC, Barcelona, September 23, 2004

cross sections 5
Cross sections (5)
  • 1.37 MeV line 1.369 MeV (24Mg*) + 1.370 MeV (55Fe*) + 1.367 MeV (59Ni*)

S=3S=4.5

a: 24,25,26Mg(p,x)24Mg*85.8%74.5%

b: 28Si(p,x)24Mg*7.2%0.9%

c: 56Fe(p,x)55Fe* 1.1% 0.1%

d: 24Mg(,’)24Mg*5.3%22.2%

e: 56Fe(a,n)59Ni* 0.6% 2.3%

IEEC, Barcelona, September 23, 2004

slide18

With the 1.63 and 1.37 MeV lines

  • etheory=20% (due to s) added in quadrature to edata for the 2probabilities
  • Goodness-of-fits:
  • Ambient medium  coronal
  • but ASEP(C) is too high
  • a/p=0.1 is favored. Then Ne/O0.15 and Mg/O0.20

The Dec 16, 1988 Flare. Not included in the probability calculations. Ambient  photosph. ?

IEEC, Barcelona, September 23, 2004

slide19

The Dec 16, 1988 Flare. Not included in the probability calculations. Ambient  photosph. ?

With DS from F2.22/F6.13 only

  • same results, but on average the probabilities are slightly lower as DS

IEEC, Barcelona, September 23, 2004

slide20

The C abondance in the interaction region

With a/p=0.1

(C/O)SEP=0.460.01

(Reames 1999)

(C/O)pho=0.500.08

(Lodders 2003)

  • Good consistency of the 3 probability distributions
  • From maximum likelywood: (C/O) = 0.28  0.03 (1s) 0.28  0.08 (2s)

IEEC, Barcelona, September 23, 2004

a new photospheric c abundance
A new photospheric C abundance ?

speculative

  • (C/O)chr~0.3 but (C/O)pho=0.5 ?
  • Apho(C) and Apho(O) are uncertain: recent substantial revisions (NLTE, 3D models)
  • A reduced Asol(C) would better fit the C abondance gradient in the Galactic disk (see Hou et al. 2000, fig. 6)
  • Anders & Grevesse (1989)
  • Grevesse & Sauval (1998)
  • Holvecker (2001)
  • Lodders (2003)
  • Asplund et al. (2004), A&A for O, in prep. for C

for a/p=0.1

IEEC, Barcelona, September 23, 2004

the photospheric 3 he abundance
The photospheric 3He abundance*

Neutrons

2.22 MeV

ne

n

n

n

3He

p

e-

H

p

3H

  • The time evolution of the 2.22 MeV line emission is sensitive to Apho(3He):

s{3He(n,p)3H}1.6·104s{1H(n,g)2H}

 tNRC = 1 / {n(3He)·sNRC·vn}

= tRC (H/3He)  6.25·10-5

  • Neutron-production time history  prompt g-ray line emission (good quality data with SPI)

*Not measured by atomic spectroscopy

IEEC, Barcelona, September 23, 2004

the magnetic loop model

Chromosphere

Photosphere

Strong PAS

No PAS

The magnetic loop model

(Hua, Lingenfelter, Murphy, Ramaty...)

isotropic accelerated-

particle release

constant B

  • MHD turbulence pitch-angle scattering

CORONA

magnetic mirroring

(sin2  B)

CHROMOSPHERE

PHOTOSPHERE

B  (pressure)d

“loss cone"

  • No PAS (mean free path   ): “fan beam“ of interacting particles (i.e. parallel to the solar surface)
  • Strong PAS: loss cone continuously repopulated  “downward beam“

Hua et al. (2002)

IEEC, Barcelona, September 23, 2004

slide24

Calculated 2.22 MeV lightcurves

  • Monte-Carlo code (Hua et al. 1987, 2002) to simulate: (i) the propagation and interaction of the accelerated particles (ii) the neutron production and propagation (iii) the 2.22 MeV line production and absorption
  • For instantaneous release of the accelerated particles, the 2.22 MeV lightcurves fall faster with increasing PAS (decreasing l) andincreasing 3He/H (see Murphy et al. 2003)

IEEC, Barcelona, September 23, 2004

slide25

The photospheric 3He abundance: results

fan beam

downward beam

  • The two free parameters are stronglycorrelated
  • l from 4.44 and 6.13 MeV line shapes more accurate 3He/H
  • Solar neutron measurements (monitors + CORONAS/SONG) could help...

IEEC, Barcelona, September 23, 2004

slide26

Summary

  • From g-ray spectroscopy of the 2003 Oct 28 solar flare with SPI:

- energy spectrum of the accelerated ions (g-ray line fluences)

- accelerated a/p ratio (g-ray line shapes and fluences)

- amount of PAS in magnetic loop/angular distribution of the interacting particles (g-ray line shapes and 2.22 MeV lightcurve)

 acceleration and transport processes

- ambient C abundance (g-ray line fluences)

- ambient 3He abundance (2.22 MeV lightcurve)

 solar composition and atmospheric response

  • Much more to do:

- timing analyses using the ACS (and radio data)

- analyses of the 2003 Nov 4 flare (near the solar limb !)

...

IEEC, Barcelona, September 23, 2004