Tapping the full potential of LOFAR cosmic-ray mass composition measurements with next-generation Monte Carlo simulations of radio emission from extensive air showers

• Applicant: Dr. Tim Huege
• Subject Area: Astrophysics and Astronomy ; Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 445154105

• Final Report Year: 2024

Final Report Abstract

Charged particles with energies much higher than produced in human-made accelerators such as the Large Hadron Collider continuously arrive at the Earth from space. Their origin is one of the great mysteries of the field of Astroparticle Physics. These so-called “cosmic rays” initiate particle cascades called “extensive air showers” in the Earth’s atmosphere. Due to interaction with the Earth’s magnetic field and ionisation of the atmosphere, these particle showers emit short radio pulses in the frequency range from a few tens of MHz to a GHz. Radio antenna arrays on the ground, in particular the Low Frequency Array (LO- FAR) and in the future the low-frequency part of the Square Kilometre Array (SKA) can measure these radio signals to determine the arrival direction, energy and mass of the primary particles. In this project, functionality to predict such radio signals was implemented in the next-generation CORSIKA 8 Monte Carlo code for the simulation of particle cascades in the Earth’s atmosphere. The predictions by two independent formalisms for the calculation of radio signals was compared and the results were validated against previous simulations with the predecessor code CORSIKA 7 as well as the ZHAireS code. Very good agreement was found between all of these implementations, providing trust in the predictions regarding their fundamental role to determine the absolute energy and the mass of the cosmic-ray particles. Furthermore, parallelization techniques for these compute-intensive simulations were explored and a proof of principle parallelized implementation was made and benchmarked. Finally, a new analysis strategy was devised and benchmarked to determine the mass of a primary cosmic ray not only from the radio signal intensity distribution on the ground – which is used so far – but also using information about the pulse shape as is encoded in the frequency spectrum of the radio signals. While for LOFAR such an approach is not feasible because of the very resonant and narrow-band response of the used antennas, for the upcoming SKA the feasibility has been demonstrated and a method has been developed that can be refined once first SKA data become available.

Publications

• A high-precision interpolation method for pulsed radio signals from cosmic-ray air showers. Journal of Instrumentation, 18(09), P09005.
  Corstanje, A.; Buitink, S.; Desmet, M.; Falcke, H.; Hare, B.M.; Hörandel, J.R.; Huege, T.; Jhansi, V.B.; Karastathis, N.; Krampah, G.K.; Mitra, P.; Mulrey, K.; Nelles, A.; Nivedita, K.; Pandya, H.; Scholten, O.; Terveer, K.; Thoudam, S.; Trinh, G. & ter, Veen S.
  
• Monte-carlo simulation of the effective lunar aperture for detection of ultra-high energy neutrinos with LOFAR. The European Physical Journal C, 83(12).
  Krampah, G. K.; Buitink, S.; Bray, J. D.; Corstanje, A.; Desmet, M.; Falcke, H.; Hare, B. M.; Hörandel, J. R.; Huege, T.; Jhansi, V. B.; Karastathis, N.; Mulrey, K.; Mitra, P.; Nelles, A.; Pandya, H.; Scholten, O.; ter Veen, S.; Thoudam, S. & Winchen, T.
  
• Reconstructing air shower parameters with MGMR3D. Physical Review D, 108(8).
  Mitra, P.; Scholten, O.; Trinh, T. N. G.; Buitink, S.; Bhavani, J.; Corstanje, A.; Desmet, M.; Falcke, H.; Hare, B. M.; Hörandel, J. R.; Huege, T.; Karastathis, N.; Krampah, G. K.; Mulrey, K.; Nelles, A.; Pandya, H.; Thoudam, S.; de Vries, K. D. & ter, Veen S.