FARSim: a fast RF-chain-aware trigger-screening surrogate for radio detection of ultra-high-energy cosmic rays
Abstract
Radio arrays provide a scalable route to detecting extensive air showers from ultra-high-energy cosmic rays, but trigger studies for candidate layouts are expensive when every energy, arrival direction, core position and trigger configuration is evaluated with full radio simulations. We present FARSim, a fast surrogate framework that reuses a reduced library of ZHAireS reference footprints to reconstruct ground-plane radio emission and to estimate trigger-relevant observables. The method combines vector geomagnetic and charge-excess field decomposition, geomagnetic-angle and energy scaling, geometrical projection, contour-based core sampling and event-rate integration. We evaluate an independent validation set of 1999 ZHAireS showers; 941 events satisfy the predefined radial-support and station-count requirements and yield a median event-level relative RMSE of 9.4% and a median Pearson coefficient rP=0.965 for the reconstructed geomagnetic lateral profiles. We further extend the peak-field surrogate to time-domain electric-field synthesis by combining the predicted three-component peak-field vector with geometry-dependent normalized pulse templates. Propagating these traces through an RF-chain response enables voltage-domain threshold and L1-trigger diagnostics. When evaluated at the true peak amplitude, the time-domain extension reaches a median vector-waveform R2 of 0.986 over 2112 ZHAireS traces held out from pulse-shape model fitting. FARSim is therefore intended as a rapid, physics-informed screening layer for array-layout and trigger studies; absolute exposure predictions and detector commissioning remain the role of full end-to-end simulations.
Related
- ECLAIRs: The SVOM High-energy Transient Trigger Camera
- A dual-polarization whitened-template trigger for real-time radio detection of extensive air showers
- A Multi-Mission Detection Framework for High-Energy Transients: Application to a 13-year Fermi/GBM and Swift/BAT Sample
- Corrected detector-level reconstruction of inclined radio air showers from trigger-level ADC waveforms
- A Deep Neural Network based Level-1 Trigger for the Magnetic Monopole Search in the SCEP Experiment
BibTeX
@misc{xu2026farsim,
title = {{FARSim: a fast RF-chain-aware trigger-screening surrogate for radio detection of ultra-high-energy cosmic rays}},
author = {Xin Xu and Pengfei Zhang and Fufu Yang and Pengxiong Ma and Ramesh Koirala and Chao Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2605.28373},
eprint = {2605.28373},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.28373},
}
RIS
TY - UNPB
TI - FARSim: a fast RF-chain-aware trigger-screening surrogate for radio detection of ultra-high-energy cosmic rays
AU - Xin Xu
AU - Pengfei Zhang
AU - Fufu Yang
AU - Pengxiong Ma
AU - Ramesh Koirala
AU - Chao Zhang
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2605.28373
UR - https://arxiv.org/abs/2605.28373
AB - Radio arrays provide a scalable route to detecting extensive air showers from ultra-high-energy cosmic rays, but trigger studies for candidate layouts are expensive when every energy, arrival direction, core position and trigger configuration is evaluated with full radio simulations. We present FARSim, a fast surrogate framework that reuses a reduced library of ZHAireS reference footprints to reconstruct ground-plane radio emission and to estimate trigger-relevant observables. The method combines vector geomagnetic and charge-excess field decomposition, geomagnetic-angle and energy scaling, geometrical projection, contour-based core sampling and event-rate integration. We evaluate an independent validation set of 1999 ZHAireS showers; 941 events satisfy the predefined radial-support and station-count requirements and yield a median event-level relative RMSE of 9.4% and a median Pearson coefficient r_P=0.965 for the reconstructed geomagnetic lateral profiles. We further extend the peak-field surrogate to time-domain electric-field synthesis by combining the predicted three-component peak-field vector with geometry-dependent normalized pulse templates. Propagating these traces through an RF-chain response enables voltage-domain threshold and L1-trigger diagnostics. When evaluated at the true peak amplitude, the time-domain extension reaches a median vector-waveform R^2 of 0.986 over 2112 ZHAireS traces held out from pulse-shape model fitting. FARSim is therefore intended as a rapid, physics-informed screening layer for array-layout and trigger studies; absolute exposure predictions and detector commissioning remain the role of full end-to-end simulations.
ER -