1. Diagnostics and constraints for relativistic electron and ion acceleration in solar flares N. Vilmer LESIA –Observatoire de Paris Ascona_June 7-11 2005

2. X/  -ray spectrum RHESSI Energy range Pion decay radiation (ions > 100 MeV/nuc) sometimes with neutrons Ultrarelativistic Electron Bremsstrahlung Thermal components Electron bremsstrahlung  -ray lines (ions > 3 MeV/nuc) T= 2 10 7 K T= 4 10 7 K SMM/GRS Phebus/Granat Observations GAMMA1 GRO GONG

3.  -ray and neutron event on 03/06/82 (from Chupp et al, 1987): -Time extended neutron production at the Sun (~ 600s) -First GeV protons accelerated in  t <16s at the beginning of the flare -Neutron Emissivity at the Sun: 7.4 10 31 E –2.4 Neutrons/MeV/sr for 100<E<2000 MeV - Spectral slope in agreement with the one deduced from neutron decay proton measurements

4.  -ray and neutron event on 24/05/90 24 May solar flare: GOES X9.3, N36 W76 One of the largest neutron event: N >100 MeV = 3.5 10 30 n sr -1 Impulsive phase  75 MeV (2nd peak) Extended phase, duration > 8 minutes: High-energy  -rays  100 MeV Pion-decay radiation from 2nd peak of the impulsive phase

5.  -ray and neutron event on 24/05/90 From Talon et al., 1993 Debrunner et al 1997 PHEBUS/GRANAT observations High Energy  -rays Solar neutrons Spectral evolution of high-energy  -rays Deduced solar neutron production time profile (i.e. pion time profile) NM CLIMAX observations of solar neutrons and prediction for a time extended neutron production

6. Background subtracted count spectra From PHEBUS/GRANAT Full line: one of the best fits with electron and pion contributions Dotted line: electron contribution Background subtracted count spectrum From 300 keV to 100 MeV Full line: one of the best fits with one electron bremsstrahlung component & pion contribution Dotted line: electron component Electron bremsstrahlung component: A e = 1 10 5  = 2 E roll = 40 MeV Proton component:  =2 N tot = 8 10 31 E max = 750 MeV  -ray lines Vilmer et al, 2003

7. Proton spectra and numbers from pion decay radiation and  -ray line radiation and neutron observations? Do we have a single energetic ion population from a few MeV/nuc to a few GeV/nuc

8. Ion spectrum with  =2 from a few Mev to E max : no compatibility Ion spectrum with  =3 from a few Mev to E max : only with E max = 750 MeV BUT GeV neutron production!! Ion spectrum with  =4 from a few Mev to E max : OK if E max > 2 GeV for spectra 1 to 3 BUT not enough pion production for spectrum 4!! No single shape of energetic ions from MeV to GeV Evidence of spectral breaks? Other forms of accelerated energetic spectra? Also found for other events (e.g. Kocharov) (see some of the simulations of particle acceleration by Dauphin et al)

9. X/  -ray spectrum RHESSI Energy range Pion decay radiation (ions > 100 MeV/nuc) sometimes with neutrons Ultrarelativistic Electron Bremsstrahlung Thermal components Electron bremsstrahlung  -ray lines (ions > 3 MeV/nuc) T= 2 10 7 K T= 4 10 7 K Phebus/Granat observations

10. Bremsstrahlung and Synchrotron Emitting Electrons (I) Simple relationship between the spectral indexes of cm-mm and HXR/GR producing electrons Spectral index  from X-ray obs Thick target production from electrons Electron flux: F(E,t)  x from X-ray obs Simple relationship between electron flux in the X-ray source and instantaneous number of electrons in the gyrosynchrotron emitting source (  r) F(E,t) ~ N(E,t)/T(E) with T(E) escape time  r ~  x =  + 1 Gyrosynchrotron Note also: obs ~  L 2 B Higher frequencies from higher energy electrons

11. Bremsstrahlung and Synchrotron Emitting Electrons (II) Mm-wave emission (86 GHz) produced by high energy electrons (  1 MeV) with a flatter spectrum than 100 keV X-ray spectrum (e.g. Kundu et al, 1994, White, 1999) Early in the flare: production of relativistic electrons on short time scales 2 components of electron populations or result of acceleration process?

12. Electron-Dominated Events First observed with SMM (Rieger et al, 1993) Short duration (s to 10 s) high energy (> 10 MeV) bremsstrahlung emission No detectable GRL flux Photon spectrum > 1 MeV (  X  -1.5—2.0) For 2 PHEBUS events o if W i>1MeV/nuc  W e>20 keV oNo detectable GRL above continuum oWeak GRL flares? Vilmer et al (1999) PHEBUS BATSE

13. Bremsstrahlung and Synchrotron Emitting Electrons (III): Electron « broken » energy spectra Many evidence from HXR/GR observations that hardening of electron spectra above a few hundred keV (i.e. electron dominated disk event but also GRL events) Evolution of the break energy in the course of the event Relation between mm/cm emitting electrons and electrons above Eb PHEBUS& Bern Trottet et al (1998)

14. Trottet, Vilmer et al. 1998 Bern and PHEBUS/GRANAT observations

15.  = radio spectral index Peak c - from HXR/GR  = 4.1 for E<Eb  = 1.5 for E>Eb -observed  = 1.5 Peak d - from HXR/GR  = 2.7 for E<Eb  = 1.2 for E>Eb -observed  = 1.3 Trottet, Vilmer et al. 1998

16. Bremsstrahlung and Synchrotron Emitting Electrons (IV): Production of submm emissions by ultrarelativistic electrons? First detection at 212 GHz Now also at 405 GHZ (Kaufman et al, 2002,2004) From Trottet, Raulin, Kaufman et al, 2002 Gyrosynchrotron emission From power law energy distribution with  = 2.7 Corresponding to a mid size electron-dominated event above > 100 kev (no observations)

17. Bremsstrahlung and Synchrotron Emitting Electrons (V): Production of submm emissions by ultrarelativistic electrons? spectre Radio emitting electron spectra harder than the X-ray observed one Consistent with  = 2.3 in II and  = 3.5 in III and B=500G But electrons of energies around 10 MeV needed Breaks? (from Lüthi et al, 2004) To be further investigated with flares also observed above a few MeV II III Rise?

18. Analyse spectrale X/centimétriq ue = -1.2 (centimétrique)  δ = -2.7 (électrons) = -1.2 (centimétrique)  δ = -2.7 (électrons)  =1.22-0.9  (Dulk et March, 1982) 09:49:10-09:50:00 09:57:00-09:57:30 09:58:10-09:58:40 09:57:40-09:58:00 09:58:40-09:59:50 2eme phase = -1.2 3 November 2003 event From Dauphin et al, 2005

19. Hypothèse: électrons rayonnent dans les X en cible épaisse (Brown, 1971) + propagation libre entre sources X et centimétrique: γ=δ+1(photons)= -1.7 Flux total observé Flux du bruit de fond Fit reproduisant le mieux le flux total – le flux du bruit de fond -1.6 raie du bruit de fond Analyse spectrale de RHESSI  Indice spectral des photons = -1.6 Population d’électrons énergétique émettant le rayonnement X > 500 keV compatible avec le rayonnement centimétrique Rear detectors (2 and 7 excluded) no pulse pile up correction Binning code 12 1 keV 3 to 60 keV 2 keV to 120 keV 5 keV to 250 keV 10 keV to 2250 keV 50 keV 2250 keV to 7200 keV 200 keV 7.2 MeV to 17 MeV + special binning around 511 keV and 2.2 MeV line 2003/11/03 09:58:49.999 2003/11/03 10:01:29.999 4.00969 3.26291 581.398 1.61146 1.4129 0

20. November 4, 2003 flare spectra OVSA Itapetinga SST Kaufmann et al, 2004) A new component Starting from 200 GHz? In relationship with High frequency radiations

21. Observations Of high energy radiation By SONG/CORONAS Myagkova et al, 2004

22. 2003 October 28 Trottet et al. 2005 in prep. Koronas Also for the 28 October flare See Trottet et al