| "Chanruangrith Channok,1 David Ruffolo..." |
| Chanruangrith Channok,1 David Ruffolo,1 | |
| Mihir Desai,2 and Glenn Mason2 | |
| 1THAILAND 2USA |
| Slide 2 |
| Slide 3 |
| "Fe/O at IP shocks..." |
| Fe/O at IP shocks is depleted relative to ambient values | |
| Larger decrease at higher energy |
| Spectra and abundances for Nov. 24 2001 IP shock |
| Why do ESP spectra roll
over at ~ 0.1 - 10 MeV/n? (data - see also: Gosling et al. 1981; van Nes et al. 1985) |
| Possible mechanisms suggested by Ellison & Ramaty (1985) | |
| shock thickness ~ κ/u energy is too low | |
| drift over shock width rollover at ~ 100 MeV/Q | |
| finite time for shock acceleration considered here | |
| (see also: Klecker et al. 1981; Lee 1983) |
| Finite-Time Shock Acceleration |
| Probability approach (like Bell 1978, Drury 1983) | |
| Acceleration rate, r = 1/Δt Escape rate, e | |
| Time at present (age of shock), t | |
| Simulation parameters: | |
| λ = λ0 (P/ MV)α so vary λ0 and α (shorter λ0 is equivalent to longer time duration) | |
| Time t fixed by observations, v0 = 200 km/s in wind frame, shock angles & speeds as observed. |
| We solve the PDE É |
| Rollover energy (Ec /A) |
| Slide 10 |
| Event #3: λ0 = 0.24 AU, α = 0.18 |
| Event #2: λ0 = 0.042 AU, α = 0.10 |
| Event #1: λ0 = 4.0x10-3 AU, α = 0.07 |
| Fe/O ratios |
| Slide 15 |
| É but wait Ð thereÕs
more! Key processes of interplanetary transport |
| Pitch-angle transport equation [DR, ApJ Õ95] |
| "Fitting SEP data" |
| Fitting SEP data | |
| Simultaneous fit to intensity vs. time | |
| anisotropy vs. time | |
| Optimal piecewise linear injection (least squares) | |
| Optimal scattering mean free path, λ [Ruffolo et al. 1998] | |
| Optimal magnetic configuration [Bieber et al. 2002] | |
| Magnetic Configurations |
| Results of fitting GLE
data (relativistic solar protons) |
| Bastille Day: July 14, 2000 - magnetic bottleneck | |
| [Bieber et al. 2002] | |
| Easter: April 15, 2001 - full Spaceship Earth network, | |
| 1-minute timing of injection [Bieber et al. 2004] | |
| October 22, 1989 - injection along both legs of a closed interplanetary loop [poster, this meeting] | |
| October 28, 2003 É well, we donÕt claim to understand everything É [Bieber et al. 2005] | |
| January 20, 2005 - possible effect of self-generated waves: nonlinear transport! [poster, this meeting] |
| Comparison with EM timing |
| Slide 22 |
| Thank you for your
attention ขอบคุณครับ |
| Slide 24 |
| Slide 25 |
| Early observations [Bryant et al. 1962] |
| Slide 28 |
| Upstream and SEP Abundances
(Desai et al. 2003 ApJ 558, 1149). |
| Upstream material comprises ~30% contribution from impulsive flares, and ~70% from large gradual SEPs |
| Slide 30 |
| Fe/O Ratio at shock versus Fe/O ratio upstream (Desai et al. 2003 ApJ vol. 558, 1149) |
| 3. Particle acceleration in
space: Shock acceleration |
| Fundamental mechanism of shock acceleration |
| Slide 34 |
| Slide 35 |
| Slide 36 |
| Slide 37 |
| Slide 38 |
| Slide 39 |
| Slide 40 |
| Slide 41 |
| Application to an
interplanetary shock: What if e, r vary with time? |
| Physical characteristics of a shock change greatly as it moves out from the Sun | |
| Observations: high energy particles are accelerated only when shock is near the Sun | |
| Near Sun: tacc (=1/r) was low, t /tacc was high, spectrum does not roll over until high energy (rollover mechanism not clear) | |
| Interplanetary space: tacc greatly increased | |
| Effectively decouple SEP, ESP acceleration |
| r, e varying - ODE model |
| More model parameters ... |
| Numerical Results |
| Four Lines of Work: |