Talk 1: Probing astroparticle and atmospheric phenomena: A decade of physics, computing, and instrumentation at GRAPES-3

by Dr B Hari Haran (TIFR)

Monday 21 Sept 2026, 14:30 → 16:30 Asia/Kolkata

AG 66 (TIFR, Mumbai)

Over the past decade at the Cosmic Ray Laboratory, Ooty, observational astroparticle physics and atmospheric phenomena were investigated through high-precision measurements of cosmic-ray secondaries, complemented by dedicated computing and software infrastructure. Key physical breakthroughs achieved using the GRAPES-3 experiment include the discovery of a 1.3 GV thundercloud potential, the characterization of geomagnetic storms during major coronal mass ejections, and the detection of global atmospheric Lamb waves triggered by the 2022 Hunga Tonga volcanic eruption. These scientific insights were enabled by key technical contributions, including custom modifications to the CORSIKA Monte Carlo package to model atmospheric electric field dynamics and optimize low-energy cosmic-ray simulations via geomagnetic cutoff rigidity—halving simulation times as the first Indian contributions to the package. To process these complex physical models, ‘g3analysis' was developed — a CERN-ROOT based framework exceeding half a million lines of code, supported by an in-house high-performance computing cluster (1280 CPU threads, ~700 TB redundant storage) designed and maintained from 2014 to 2022 to power numerous Ph.D. theses and high-impact publications.