shock geometry and particle injection at shocks
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Shock geometry and particle injection at shocks
Discussion: M. Desai vs H. Cane --- Do flare particles “see” CME shocks at all?
J. Giacalone: Electron acceleration at shocksA.Tylka: Perp. shock to explain various Fe/O ratios Dietmar Krauss-Varban: shock acceleration: geometry and injection Nathan Schwadron: Insights from recent TS resultsJoseph Kota:SEP and geometry of shocksG. P. Zank (G. Li): Particle acceleration at a perpendicular shock
WG3 Session#7Thursday PM:
Electron acceleration
Jokippi and Giacalone, 2005
Geometry changing CME-driven shocks and energy dependence of Fe/O ratio
Tylka et al., ApJ 625, 474-495(2005)Tylka et al, ApJS 164, 536-551 (2006)Tylka and Lee, ApJ 646, 1319-1334 (August 1, 2006)
Fe/O vs. EnergyFe/O vs. Energy
1. A direct flare component that dominates at high energies: Cane et al. 2003; 2006.
2. CME-driven shocks accelerate “fresh” suprathermal seed ions Li & Zank 2005
3. CME-driven shocks accelerate “remnant” suprathermal flare ions.Mason et al. 1999; Tylka et al. 2001.
Intrinsic Oblique Shock Undulation
Topology counts
Kota and Jokippi 2004
Lessons from Voyager I
Remarks: 1) Parallel shock
calculation assumes wave excitation
2) Particle maximum energy at parallel shock decrease faster than maximum energy at perp. shock
3) Injection energy at Q-
perp shock much higher than at Q-par, therefore expect difference in composition
Zank et al. 2006
Maximum and injection energy for parallel and perpendicular shock
Diffusion tensor: 2 2sin cosxx bn bnκ κ θ κ θ⊥= + P
Since , the anisotropy is defined by κ κ⊥P ?
1/ 22 2 2 2 2
2 2 2
( cos )sin31
3 ( sin cos )d bn bn
bn bn
u q
v
κ κ θ θξ
κ θ κ θ⊥
⎡ ⎤+⎛ ⎞= − +⎢ ⎥⎜ ⎟ +⎝ ⎠⎢ ⎥⎣ ⎦
P
P
For a nearly perpendicular shock sin 1bnθ ;
( )
1/ 22 2 2
2 2 2
cos3 1
( cos )1
g bn
bn
ru
v r
λ θξ
λ λ θ⊥
⎡ ⎤+= +⎢ ⎥
+−⎢ ⎥⎣ ⎦
P
P
1ξ =
Anisotropy and the injection threshold
To apply diffusive shock acceleration
After session Marty et al points out “dip” maybe unphysical.
Streamer H I Lyα profiles at 1.8 & 2.2 R (May 2006) and 1.9 & 3.1 R (July 2006)
Slit positions for July 2006
Slit position for May 2006
• What is the injection problem?
• Is there an injection problem?
• How perp. shocks and parallel shocks differ?
• What observations helps to discern perp. shock from parallel shock?
• Is it meaningful to talk about “perp.” and parallel shock at all?
• Can shock accelerate electrons? How do the shock do it and how do we tell?
Questions:
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