1 / 12

Particle Acceleration at a Blunt Termination Shock Nathan Schwadron (BU) Marty Lee ( UNH)

Particle Acceleration at a Blunt Termination Shock Nathan Schwadron (BU) Marty Lee ( UNH) Dave McComas (SwRI). Voyager 1 Reaches the TS – December 2004. Shocking ACR Spectra Outside TS. Stone et al., 2005.

eugene
Download Presentation

Particle Acceleration at a Blunt Termination Shock Nathan Schwadron (BU) Marty Lee ( UNH)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Particle Acceleration at a Blunt Termination Shock Nathan Schwadron (BU) Marty Lee (UNH) Dave McComas (SwRI)

  2. Voyager 1 Reaches the TS – December 2004

  3. Shocking ACR Spectra Outside TS • Stone et al., 2005 • Unexpected when the ACRs observed by V1 did not peak at the TS as had been so widely predicted • Continued to see the characteristic ACR “bump” at ~100 MeV caused by modulation

  4. The Voyager ACR Paradox • V1 Proved that ACRs were not being accelerated by the TS at the time and location where it passed through • So where and how are they accelerated? • Are ACRs generated only at special, favored acceleration regions on the shock? • Are they accelerated only at some times at any given shock location? • Are we completely wrong and ACRs are accelerated by some other means at some location further out, beyond the termination shock (e.g., Gloeckler and Fisk)? • Clearly show how little we really know about our local cosmic accelerator • Local observations beg the question of the global interaction

  5. Magnetic Geometry at a Blunt TS • TS shape taken from Zank, 1999

  6. Injection Problem Chalov, ‘05 Chalov, ‘93

  7. Injection at a Blunt Termination Shock

  8. Simple Model with Blunt TS

  9. Diffusive Drift Acceleration

  10. Diffusive Drift Acceleration

  11. Correlated ACRs & GCRs • Strong correlation shows GCRs and ACRs are moving to the nose from much farther out in the heliosheath

  12. Summary • Shape Matters !!! • Always knew that TS was blunt and not spherical, but didn’t appreciate that the TS shape drives the macro-interaction • Many sketches, drawings, and even some simulations • Explained precursor event anisotropies inside TS (Jokipii et al., 2004) • Flattening of the nose of the TS produces a macro-scale geometry that enables a simple, standard time-dependent acceleration of ACRs • Smaller θBN and lower injection energies away from nose • Higher energy particles generated on flanks where magnetic field lines have pierced the TS for longer times • Real spectra vs location will depend on actual TS shape and detailed interactions

More Related