The endpoint formalism for the calculation of electromagnetic radiation and its applications in astroparticle physics radiation from „endpoints“ antenna

Named radiation mechanisms many named radiation mechanisms in the literature Synchrotron radiation (Vavilov-)Cherenkov radiation Transition radiation and many more … these are idealized concepts for simplified problems when applied to realistic problems, they can lead to confusion: „On the Cherenkov threshold associated with synchrotron radiation in a dielectric medium“ „Cherenkov radiation from an Electron Traveling in a Circle through a Dielectric Medium“ etc … let‘s go back to basics! ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Charged particle motion: Liénard-Wiechert fields antenna delay: R/c r ^ q b continuous formulation difficult to apply in Monte Carlo codes ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Discretization of particle motion: endpoints discrete formulation for arbitrarily complex motion radiation only from endpoints r ^ b1 delay: R/c b2 antenna endpoints: decelerate from b1 to rest then accelerate from rest to b2 ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Radiation from a single endpoint time domain formulation frequency domain formulation - for deceleration from b* to rest (stopping point) + for acceleration from rest to b* (starting point) ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Reproducing Synchrotron Radiation discretize circular motion fineness dictated by Dt, nmax pairs of stopping and starting points B-field antenna ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Reproducing Synchrotron Radiation direct calculations in time-domain and frequency-domain agreement with FFT of the other domain localized signal: time-domain is better for this problem ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Reproducing Transition Radiation beautifully reproduced, for details please see arXiv:1007.4146 ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Application: Askaryan Radiation shower particle track near medium surface θC “Cherenkov” shock wave from “static field” not reproduced by (current) endpoint formalism significant in the near-field (E ~ 1/R2) vanishes in vacuum and thus in “Formation Zone” Radio emission from acceleration/deceleration (time-variation of charge excess in shower) modelled by endpoint formalism dominant in far-field (E ~ 1/R) arises also in vacuum No „Formation Zone“: Askaryan emission does not vanish for cosmic ray showers near lunar surface. ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Application: EAS Radio Emission (REAS3) earlier Monte Carlos missed radiation due to „creation and destruction“ of particles (time-variation of Nparticles) REAS3 employs endpoint formalism – consistency! pulses become bipolar spectra fall to zero at frequency zero breakthrough: agreement between microscopic (REAS3) and macroscopic (MGMR) models ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Application: EAS Radio directly in CORSIKA simple implementation very efficient calculation, fast and numerically stable full CORSIKA information, no information loss refractive index effects included ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Conclusions named „emission mechanisms“ only apply to idealised situations endpoint formalism works for arbitrarily complex problems is very well-suited for implementation in Monte Carlo codes works in time- and frequency domains successfully applied endpoint formalism in astroparticle physics Askaryan emission does not vanish near medium surface reconciliation of microscopic (REAS3) and macroscopic models for radio emission from EAS ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Backup Slides ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Radiation from a single endpoint in vacuum relativistic beaming in medium disconti-nuity at Cherenkov angle ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Radiation from a single endpoint in a medium ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Achievable precision ICRC 2011 Beijing #0653, see also arXiv:1007.4146

Simulating Transition Radiation ICRC 2011 Beijing #0653, see also arXiv:1007.4146