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: