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Luke Drury Dublin Institute for Advanced Studies Luke Drury Dublin Institute for Advanced Studies Particle Acceleration in the Universe.

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Presentation on theme: "Luke Drury Dublin Institute for Advanced Studies Luke Drury Dublin Institute for Advanced Studies Particle Acceleration in the Universe."— Presentation transcript:

1 Luke Drury Dublin Institute for Advanced Studies Luke Drury Dublin Institute for Advanced Studies Particle Acceleration in the Universe

2 Moscow 1987 Adelaide 1990 Leeds 1991 Dublin 1991 (birth of Auger project) Some ICRC history...

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4 The US president was George Bush; War broke out in the Gulf! After the 1991 ICRC I said we would never again hold another meeting of more than 100 people. However, last year we cohosted with Armagh Observatory the NAM2003 meeting, also ca 500 participants. On both occasions: Not statistically significant, but....

5 In the heliosphere in the Galaxy at cosmological scales Particle acceleration in the Universe Universal phenomenon - seen:

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7 Very common sequence... Sudden release of energy Mass ejection Shock formation Particle acceleration CMEs, SNRs, GRBs etc...

8 Supersonic flow Hits obstacle Shock forms Particle acceleration Other common pattern.... Earth’s bow shock, pulsar wind, AGN jets etc..

9 Cas-A as seen in X-rays by Chandra

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11 Shock acceleration... Non-relativistic version reasonably well understood. Injection still a problem. Nonlinear effects difficult to include in models, but generally good agreement. Considerable progress on relativistic case.

12 Not the only game in town.... Magnetic reconnection Second-order Fermi Large E fields (pulsars?) But seems to be the most important one....

13 Ambient compressed? Amplified? Self-generated? However, need a (non-uniform) magnetic field....

14 Ambient field SNR

15 Field amplification McKenzie and Voelk, 1982 Bell and Lucek, 2001 Lucek and Bell, 2001 Bell, 2004

16 Field generation Frederiksen, J T et al, 2004, ApJ 608 L13. Califano, F et al, 1998, Phys Rev E, 57, 7048. Weibel, E 1959, PRL 2 83.

17 Growing evidence for enhanced magnetic fields in young SNRs. GRB models assume strong fields. Equipartition fields seem to work in AGN hot-spots. Plausible mechanisms exist

18 Faster acceleration Higher cut-off energies Greater radiative losses for electrons Stronger magnetic fields mean.... but also...

19 Shock acceleration seems OK if we allow field amplification by shocks. There are other possibilities though... Need more and better data (over to you, Alan...) Conclusions

20 The problem of the origin of cosmic rays will be solved by more work and less talk! Rutherford, ca 1940


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