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The EVA code

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  1. The EVA code Macroscopic modeling of radio emission based on full MC simulations including a realistic index of refraction Krijn de Vries ¹ Olaf Scholten ¹ Klaus Werner ² KVI/RUG Groningen ¹ SUBATECH, University of Nantes ²

  2. Radio Emission Mechanisms:Geo-Magnetic current • e+e- pairs are deflected in the Earth Magnetic Field due to the Lorentz force. • Net macroscopic current in the direction of the Lorentz force. 1

  3. RadioEmission Mechanisms:Charge excess • Several processes give rise to a net negative charge of the shower front (Askaryan): 1. Compton scattering 2. Knock out by shower particles 3. Positron annihilation • Net negative current in the direction of movement of the shower. 2

  4. MGMR: - Parameterized current and charge distribution - Lateral particle extent ignored. - No Cherenkov effects included. EVA: - Full Monte Carlo simulations - Full 3D shower information from histograms. - Cherenkov effects included. Ingredients: Particle distributions and Currents MGMR vs EVA 3

  5. CX-MC-GEO:Full Monte Carlo version of CONEX - Provides histograms of the current and charge distributions FITMC:Fit program - Provides analytical expressions for the currents and particle distribution. EVA:Coherent radio emission from current and charge distributions - Including Cherenkov effects The EVA code 4

  6. CX-MC-GEO+MCFIT:The shower profile Fit Histo Ne(t’) Shower time t’(μs) K. Werner, et. al. arXiv:1201.4471 5

  7. CX-MC-GEO+MCFITThe Macroscopic currents Jz/Nec Jx,y/Nec Shower time t’(μs) Fit Shower time t’(μs) Histo Geomagnetic Current Charge-excess Current K. Werner, et. al. arXiv:1201.4471 6

  8. CX-MC-GEO+MCFIT:The particle distributions in the shower front mm scales !! 7 K. Werner, et. al. arXiv:1201.4471

  9. Longitudinal particle distribution close to the shower axis, very sharp!!! CX-MC-GEO+MCFIT:The particle distributions in the shower front Lateral particle distribution in the pancake: <r>=1.3m Fit Histo Fit Histo 1 cm r(m) h(m) K. Werner, et. al. arXiv:1201.4471 8

  10. EVA - Emission MechanismsFrom Currents to radiation. D can vanish for realistic cases, n = n(z) ≠ 1  Cherenkov ! 9

  11. EVA - Retarded distance Ne·10-11 t': emission time t: observer time -t’(μs) t(μs) 10

  12. -The atmosphere is given by the US standard atmosphere. -Ray tracing possible, shown to be not important. SL EVA - The Atmosphere and index of refraction Curved 60° b = 100 m -t’(μs) t(μs) - Therefractivity is given by the law of Gladstone And Dale: -t’(μs) 90° b = 100 m t(μs) 11

  13. EVA - The Electric Field Cherenkov effects Square-root divergence, can be safely integrated for smooth currents and weight functions! Cherenkov effects can be included due to the finite extent of the shower front!!!!!! 12

  14. EVA vs MGMR 800 meters 0.5 0.5 EVA n = n(z) EVA n = 1 E(μV/m) 0.2 E(μV/m) -1.5 -1.5 0 t(μs) t(μs) 0 3 E(μV/m) MGMR n = 1 L = 2 m -1.5 0 3 t(μs) 13

  15. EVA vs MGMR 100 meters 500 100 E(μV/m) EVA n = n(z) E(μV/m) EVA n = 1 100 -4500 -900 t(μs) t(μs) 0 0.05 0 E(μV/m) MGMR n = 1 L = 2 m -500 t(μs) 0.05 0 14

  16. EVA vs MGMR 0.5 500 E(μV/m) E(μV/m) -4500 3 0.05 0 0 t(μs) t(μs) d=100 meters d=800 meters 15

  17. To obtain the EVA package, please contact Krijn de Vries by sending an e-mail to dvries@kvi.nl The EVA package: 16

  18. The EVA package is developed: The code is based on Full Monte Carlo air shower simulations Cherenkov effects can be included due to finite extent of the current distributions (particles in the shower front) Differences between EVA and MGMR are due to the shower front and Cherenkov effects MGMR works good at large observer distances: Advantage fast! The EVA package is public! Conclusions 17

  19. To obtain the EVA package, please contact Krijn de Vries by sending an e-mail to dvries@kvi.nl The EVA package: 16

  20. General Pulse Shape Far from the Cherenkov distance: Cherenkov distance: Sharp edge of shower front Shower profile pre shower max Particle max Shower max 12