Browsing by Autor "C. A. H. Condori"

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Effects of the May 10, 2024 Solar Storm on the South Atlantic Anomaly: A Case Study in Bolivia
(2025) C. A. H. Condori; R. Ticona; P. Miranda; C. A. Guerrero; E. Romero‐Hernández; E. Peréz‐Tijerina; R. Raljevic; M. Subieta-Vázquez
<title>Abstract</title> We analyzed the strongest geomagnetic storm of the past two decades, which occurred on May 10, 2024, focusing on plasma data from spacecraft, Earth's magnetic field variations recorded at the Villa Remedios Magnetic Observatory, and neutron data from the 12-NM64 monitor, both located in La Paz, Bolivia. Situated within the South Atlantic Magnetic Anomaly (SAA), this region offers a unique perspective on geomagnetic disturbances, emphasizing the relevance of localized studies. The Villa Remedios Magnetic Observatory recorded a Dst drop of -560 nT, significantly larger than the -412 nT reported by the Kyoto station, underscoring pronounced regional variations likely amplified by SAA's influence. Concurrently, the neutron monitor at Chacaltaya registered a Forbush decrease on May 10, linked to coronal mass ejections (CMEs) and solar flares that occurred on May 8. This decrease was followed by a prolonged 13-day recovery, mirroring patterns observed in the Dst index. The combined data highlight the intricate interplay between solar activity and its terrestrial impacts, revealing significant correlations among CMEs, solar wind velocity, proton and electron fluxes, and geomagnetic disturbances. What did we learn from this geomagnetic storm? The importance of considering the geographical location and magnetic environment when analyzing such phenomena.
Hadronic Interaction Model Dependence in Cosmic Gamma-ray Flux Estimation Using an Extensive Air Shower Array with a Muon Detector
(Research Square (United States), 2022) S. Okukawa; Y. Katayose; M. Anzorena; Shunta Asano; C. A. H. Condori; E. De la Fuente; A. Gomi; K. Hibino; N. Hotta; A. Jiménez-Meza
Abstract Observation techniques of high-energy gamma rays using air showers have remarkably progressed via the Tibet AS$\gamma$, HAWC, and LHAASO experiments. These observations have significantly contributed to gamma-ray astronomy in the northern sky's sub-Peta electron volts (PeV) region. Moreover, in the southern sky, the ALPACA experiment is underway at 4,740\,m altitude on the Chacaltaya plateau in Bolivia. This experiment estimates the gamma-ray flux from the difference between the number of on-source and off-source events by real data, utilizing the gamma-ray detection efficiency calculated through Monte Carlo simulations, which in turn depends on the hadronic interaction models. Even though the number of cosmic-ray background events can be experimentally estimated, this model dependence affects the estimation of gamma-ray detection efficiency. However, previous reports have assumed that the model dependence is negligible and have not included it in the error of gamma-ray flux estimation. Using ALPAQUITA, the prototype experiment of ALPACA, we quantitatively evaluated the model dependence on hadronic interaction models for the first time. We evaluate the model dependence on hadronic interactions as less than 3.6\,\% in the typical gamma-ray flux estimation performed by ALPAQUITA; this is negligible compared with other uncertainties such as energy scale uncertainty in the energy range from 6 to 300 TeV, which is dominated by the Monte Carlo statistics. This upper limit of 3.6\,\% model dependence is expected to apply to ALPACA.
Hadronic interaction model dependence in cosmic Gamma-ray flux estimation using an extensive air shower array with a muon detector
(Springer Science+Business Media, 2023) S. Okukawa; M. Anzorena; Shigeru Asano; C. A. H. Condori; E. De la Fuente; A. Gomi; K. Hibino; N. Hotta; A. Jiménez-Meza; Y. Katayose