Asymmetric Backward Peaking Radiation Pattern from a Relativistic Particle Accelerated by Lightning Leader Tip Electric Field

Mert Yücemöz, Martin Füllekrug

Research output: Contribution to journalArticlepeer-review

Abstract



Terrestrial Gamma ray Flashes exhibit slopes of ionizing radiation associated with bremsstrahlung. Bremsstrahlung has a continuous spectrum of radiation from radio waves to ionizing radiation. The Poynting vector of the emitted radiation, that is, the radiation pattern around a single particle under the external lightning electric field during interaction with other particles or atoms, is not quite well known. The overall radiation pattern arises from the combination of radiation of parallel and perpendicular motions of a particle caused by the acceleration from the lightning electric field and the bremsstrahlung. The calculations and displays of radiation patterns are generally limited to a low-frequency approximation for radio waves and separate parallel and perpendicular motions. Here, we report the radiation patterns of combined parallel and perpendicular motions from accelerated relativistic particles at low and high frequencies of the bremsstrahlung process with an external lightning electric field. The primary outcome is that radiation patterns have four relative maxima with two forward peaking and two backward peaking lobes. The asymmetry of the radiation pattern, that is, the different intensities of forward and backward peaking lobes, are caused by the Doppler effect. A novel outcome is that bremsstrahlung has an asymmetry of the four maxima around the velocity vector caused by the curvature of the particle's trajectory as it emits radiation. This mathematical modeling helps to better understand the physical processes of a single particle's radiation pattern, which might assist the interpretation of observations with networks of radio receivers and arrays of γ-ray detectors.
Original languageEnglish
Article numbere2020JD033204
JournalJournal of Geophysical Research: Atmospheres
Volume126
Issue number13
Early online date12 Jun 2021
DOIs
Publication statusPublished - 16 Jul 2021

Bibliographical note

Funding Information:
M. Yücemöz would like to thank to his supervisor M. Füllekrug for all the opportunities, suggestions, guidance, reviews, and support throughout his PhD study. The Engineering and Physical Sciences Research Council (EPSRC) and MetOffice sponsor M. Yücemöz's PhD project under contract numbers EG‐EE1239 and EG‐EE1077. M. Füllekrug acknowledges support from the Natural Environment Research Council (NERC) for under grants NE/L012669/1 and NE/H024921/1. M. Yücemöz wishes to thank Dr. Adrian Hill for mathematical support in helping to solve integral with a divergence problem and his family for their support and good wishes.

Publisher Copyright:
© 2021. The Authors.

Funding

M. Yücemöz would like to thank to his supervisor M. Füllekrug for all the opportunities, suggestions, guidance, reviews, and support throughout his PhD study. The Engineering and Physical Sciences Research Council (EPSRC) and MetOffice sponsor M. Yücemöz's PhD project under contract numbers EG‐EE1239 and EG‐EE1077. M. Füllekrug acknowledges support from the Natural Environment Research Council (NERC) for under grants NE/L012669/1 and NE/H024921/1. M. Yücemöz wishes to thank Dr. Adrian Hill for mathematical support in helping to solve integral with a divergence problem and his family for their support and good wishes.

Keywords

  • atmospheric electrodynamics
  • bremsstrahlung radiation
  • dipole
  • forward & backward peaking radiation pattern
  • lightning leader tip electric field
  • radiation pattern
  • Terrestrial Gamma-Ray Flashes (TGFs)

ASJC Scopus subject areas

  • Atmospheric Science
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'Asymmetric Backward Peaking Radiation Pattern from a Relativistic Particle Accelerated by Lightning Leader Tip Electric Field'. Together they form a unique fingerprint.

Cite this