Precision measurements of cosmic ray phenomena with GRAPES-3

Cosmic rays (CRs) are the most energetic radiation in the universe, observed over 12 orders of magnitude in energy (10^8 to ≳10^20 eV). Despite continued progresses in the field, questions about their origin, acceleration mechanism, elemental composition, influences on weather and their impact on climate remain still open. The GRAPES-3, a new generation cosmic ray experiment built by TIFR at Ooty offers a unique facility to explore a number of CR phenomena including the galactic and extra-galactic CRs, their modulation in the heliosphere and the acceleration of secondary CRs in the intense thundercloud electric fields. The GRAPES-3 comprises of a dense array of 400 scintillator detectors and the largest tracking muon detector (560 m^2). Here, I will give an overview of our efforts devoted for the indigenous development of efficient scintillator detectors on the hardware front and a large-scale object oriented data analysis framework on the software front and the huge impact it made on improving the quality of data and the analysis. A unique measurement of cosmic ray anisotropy in the heliosphere will be discussed next. This will be followed by a discussion of precursor events detected prior to the arrival of coronal mass ejection at the Earth which could serve as advance warning for the space weather phenomena. Some interesting observations on the thundercloud acceleration will be presented.