For the first time in the world, researchers at the GRAPES-3 muon telescope facility in Ooty (short for Udhagamandalam) Tamil Nadu have measured the electrical potential, size and height of a thundercloud that passed overhead on December 1, 2014.
At 1.3 gigavolts (GV), this cloud had 10 times higher potential than the previous record in a cloud.
Q. What is GRAPES-3 Experiment?
GRAPES-3 (Gamma Ray Astronomy PeV EnergieS phase-3) is designed to study cosmic rays with an array of air shower detectors and a large area muon detector.
It aims to probe acceleration of cosmic rays in the following four astrophysical settings.
It is located at Ooty in India and started as a collaboration of the Tata Institute of Fundamental Research, Mumbai, India and the Osaka City University, Osaka, Japan.
Q. What is its principal area of research?
A. Measuring the potential of a Thunderstorm
Using a computer simulation and the observed Muon intensity variations, the group worked out the relationship with the electric potential of the cloud.
They calculated that the potential of the cloud they were studying was approximately 1.3 Giga Volts.
At 1.3 GV this cloud had 10 times higher potential than the previous record in a cloud.
No one has ever measured potential, size and height of a thundercloud simultaneously.
Q. What might be Utility of this study?
Learning about the properties of thunderclouds can be useful in navigation of aircraft and preventing short circuits.
Cloud structure are better assessed:
Clouds have negative charges along their lower side and positive charges on top and can be several kilometres thick..
Q. What are Muons? How are they detected?
Muons and other particles are produced when cosmic rays bombard air particles surrounding the earth.
The muons produced can have positive or negative charge.
When a positively charged muon falls through a cloud, it loses energy.
If its energy falls below 1 giga electron volt (GeV), which is the threshold of detection of the GRAPES-3 muon telescope, it goes undetected.
On the contrary, a negatively charged muon gains energy when falling through the cloud and gets detected.
Since there are more positive than negative muons produced in nature, the two effects don’t cancel out, and a net change in intensity is detected.