Roger Blandford KIPAC, Stanford with Paul Simeon and Noemie Globus Acceleration of Cosmic Rays by Interstellar and Intergalactic Shock Fronts Roger Blandford KIPAC, Stanford with Paul Simeon and Noemie Globus 14 viii 2018 VHEPU

Radio detection of UHECR Piotrowski PS4.4 JEM-EUSO Haungs PS4.4 Radio detection of UHECR Piotrowski PS4.4 JEM-EUSO 14 viii 2018 VHEPU GeV TeV PeV EeV ZeV

Mixed Composition Model CREAM Seo et al Allard PS2.3 Mixed Composition Model ACE Mewaldt et al AMS Kaskade Grande 14 viii 2018 VHEPU

UHECR Spectrum and Composition Globus PS2.3 Dipole GZK cutoff observed Heavier nuclei at highest energies 14 viii 2018 VHEPU

Refutable Comprehensive Model Mostly Diffusive Shock Acceleration Heliosphere to rich cluster accretion shocks Scaling laws Reflection as well as transmission Injection of pre-existing population Magnetic bootstrap Propagation Rigidity Charge? Background spectrum and CR-generated Refutable 14 viii 2018 VHEPU

Schematic of Shock Acceleration Sites Cluster Accretion Shock M~ 30 Filament/Circumgalactic Shock M~3 Galactic Wind Termination Shock M~10 SNR/OB M~100 Not to Scale! 14 viii 2018 VHEPU

Tycho SNR Magnetic amplification X-ray striations Currents or fields? X-ray synchrotron emission at shock front by ~50TeV electrons rL ~ 2x1015cm ~ 50 mas Thermal emission by shocked gas Magnetic amplification X-ray striations Currents or fields? Lasagna or spaghetti? Hughes 14 viii 2018 VHEPU

Cosmic Ray Protons Accelerated in SNR? Pion decay signature of cosmic ray proton acceleration in the presence of molecular gas Only observe in high density environments W44 Yang PS3.1 CR from Star Clusters George Miley ECR ~1043J Protons may escape 14 viii 2018 VHEPU

Galactic Wind Termination Shock Driven by hot SNR and Cosmic Rays Escape through buouyancy, Parker instabilities Lwind ~ 10-3 Lgal Shocks when momentum flux ~ PCGM M uncertain Highest energy particles escape upstream Recchia PS3.1 CR-Driven Wind 14 viii 2018 VHEPU

Cluster Observations and Simulations Perseus Cluster 14 viii 2018 VHEPU

Intergalactic Shocks Cluster Accretion Shocks Filament Shocks Skillman 2008 Cluster Accretion Shocks 10<M<100 Filament Shocks 3<M<10 Interior shocks 1<M<3 14 viii 2018 VHEPU

Cluster Accretion Shocks Sgas/k Measured entropy in outer parts of clusters is much greater than gas entropy after reionization DS > 10 k? Requires strong accretion shock Arise in simulations M can be as large as 100 A candidate site for UHECR acceleration Adequate power M-H nuclei 18 17 16 15 Simionescu et al Perseus cluster 14 13 r r Werner et al 14 viii 2018 VHEPU

DiffusiveShock Acceleration Statistical (kinetic) approach Distribution function – f(p,x,t) Energy in bulk motion Clouds, waves, shocks… Stochastic energy gain Fokker-Planck equation Diffusion in momentum space Wave scattering l ~ rL, D ~ rL v/3 Self-excited by particles L~D/u~Ea CR pressure Decelerates flow Changes g 14 viii 2018 VHEPU

Magnetic Bootstrap Shocks also amplify B SNR P(E) / u2 GeV TeV PeV 0.1 Shock X E GeV TeV PeV Shocks also amplify B Increases EMAX Cosmic rays create their scatterers Weibel B<<Bshock Bell l<rL(PeV) Resonant l~rL(PeV) Firehose l>rL(PeV) … X increases with E 14 viii 2018 VHEPU

In or out? Dimensionality Energy Escape Do not escape planar shock Can escape cylindrical or spherical shock Energy mfp ~ E0.5-1 Only highest energy particles escape upstream Most, lower energy particles held downstream Expansion loss in SNR Escape Limited by instability? eg Blasi 14 viii 2018 VHEPU

Scaling Laws Compromise average spectrum for M>>1 S(R) ~ R-0.3 Maximum Rigidity ~ u B R/c Field coherent on scale of largest Larmor radius rL ~p/ZeB Transmitted Pressures PCR ~ Pmag ~ r u2 /4 Rmax ~ 30 (Lshock/1034W)1/2 u81/2PV/c 14 viii 2018 VHEPU

Propagation Galactic propagation SNR accelerate to ~ 30 TV/c MHD turbulence, wandering fields at higher energy Alfven-limited propagation at lower energy UCR(R) ~R-0.3 R-.35 ~ R-0.65 SNR accelerate to ~ 30 TV/c GWTSR to ~ 1 PV/c Anisotropy Weak filaments accelerate GCR to ~ ankle Rich clusters re-accelerate GCR to ~toenails Propagation uninhibited at highest energies until Galaxy Merten PS3.1 CR transport Vittino PS3.1 Interstellar electrons and positrons Johannesson PS2.3 CR and Interstellar Emission 14 viii 2018 VHEPU

Range and Luminosity Density Allard lIGM ~ 0.1 g cm-2 t ~ 100Myr @ 100EeV(p,Fe) Pairs>pions < 10EeV Eternal < 1EeV Acceleration depends on E/Z Luminosity Density L(GV/c)~10L(PV/c) ~ 100L (10EeV) ~ 0.003 Lgal 14 viii 2018 VHEPU

Summary UHECR are energetic and luminous GCR from SNR etc to ~ 10 TeV ~0.1ZeV=1020eV; L~0.03 LGeVCR GCR from SNR etc to ~ 10 TeV Higher energy from G, CG, filamentary shocks Acceleration faster than propagation UHECR from cluster accretion shocks Reacceleration of galactic cosmic rays? 10<M<100 Highest energy are M-H nuclei escaping upstream Propagation faster than acceleration 14 viii 2018 VHEPU