Constraints on Particle Acceleration from Interplanetary Observations R. P. Lin together with L. Wang, S. Krucker at UC Berkeley, G Mason at U. Maryland, and R. Mewaldt at Caltech

Krucker and Lin 2002

Electron - 3 He-rich SEP events - ~1000s/year at solar maximum - dominated by: - electrons of ~0.1 (!) to ~100 keV energy - 3 He ~10s keV/nuc to ~MeV/nuc x10-x10 4 (!) enhancements - heavy nuclei: Fe, Mg, Si, S enhancements - high charge states - associated with: - small flares/coronal microflares - Type III radio bursts - Impulsive soft X-ray bursts (so also called Impulsive SEP events )

L=v(t-to) or L/v=t-to ~ 0.05 MeV/nuc - 1/v of 3 He (Mason & Mazur) ~1.5 MeV/nuc - 1/v for Electrons / Electrons 0.14–13 keV Electrons 20 – 350 keV Ions ~ 0.5 – 1 MeV

Electron spectrum at 1AU Typical electron spectrum can be fitted with broken power law: Break around: keV Steeper at higher energies Oakley, Krucker, & Lin 2004

Comparing spectra PHOTON SPECTRA: Power law fit to HXR spectra averaged over peak ELECTRON SPECTRA: Power law fit to peak flux Assuming power spectra: THIN: d = g – 1 THICK: d = g + 1 RESULTS: 1)correlation seen 2)values are between

Wang, Krucker, Lin, & Gosling, 2005

Wang, Krucker, Lin, & Gosling 2005

The Sun is the most energetic particle accelerator in the solar system: - Ions up to ~ 10s of GeV - Electrons up to ~100s of MeV Acceleration to these energies occurs in transient energy releases, in two (!) processes: - Large Solar Flares, in the lower corona - Fast Coronal Mass Ejections (CMEs), in the inner heliosphere, ~2-40 solar radii

X-Class Flare of 2002 July 23 00:27:20–00:43:20 UT GOES X4.8 Location: S13E72 (Lin et al. 2003)

RHESSI Gamma-Ray Flares 2002 July 23X June 17M October 28X October 29X November 2 X November 3 X November 10 X January 15X January 17X January 19X January 20X7.1 Ramaty High Energy Solar Spectroscopic Imager (RHESSI)

Mewaldt et al 2005

(Mewaldt et al. 2005)

Oct. 28, 2003, RHESSI solar count spectrum from 11:06:20 – 11:10:04 (Smith et al. 2004, Share et al. 2004) e + - e - n-capture bremsstrahlung narrow lines broad lines

Murphy 2004

Energetic Proton Power-law Exponents 28 Oct 03 2 Nov 03 S16E08 S15W56 γ-ray lines Energy range γ-ray (SEP) γ-ray (SEP) Ne/C+O 2-20 MeV (1.3) (1.7) e+/C+O MeV (2.0) (2.8) n-capt/C+O MeV (2.5) (3.0)

GOES soft X-rays RHESSI 2.2 MeV line RHESSI keV RHESSI hard X-rays WIND/WAVES radio WIND/3DP electrons

20 Jan 05 Flare RHESSI Gamma-ray Spectrum - 20 Jan 05 Flare

In the Jan 20 Event the high energy particle-intensities reach Earth just minutes after the x-rays from the flare

RHESSI X-ray imaging during HXR peak: X-ray imaging Two ribbon flare with HXR footpoints (contours) with thermal loop (image)

Initial flare phase: GOES SXI & RHESSI enhanced SXR emission Dimming After 06:40, HXR footpoints dominate 6:40:30

Timing Red line (06:48UT): Solar release time derived from onsets at 1 AU assuming first arriving particles travel with the speed of light along L=1.2 AU LASCO (06:54UT): Around ~3 solar radii; lines show height assuming a constant velocity. For v=2500km/s, CME could be at ~1.5 solar radius at particle release time. Red crosses: Rising SXR loops (top of SXI emission) 2.2 MeV peaks at 06:47:30UT HXRs peak at 06:45:00UT