doi:10.1038/nindia.2017.53 Published online 3 May 2017
By using very low-frequency radio waves and two remotely placed receivers, physicists have shed light on how solar flares affect the lower ionosphere. The analyses indicate that small solar flares can be detected with portable antenna systems even if a radio-waves receiver is located in a polar coastal region compared to an equatorial region1.
This opens up new opportunities to monitor and study how solar radiation affects the Earth’s ionosphere, an integral region for satellite communications.
It is difficult to study the properties of lower ionosphere by sending balloons and satellites. This region, forming after sunrise, can only be explored by sending low-frequency radio waves which, when reflected back to Earth, do not attenuate.
Scientists from the Tripura University in Tripura and Vikram Sarabhai Space Centre in Trivandrum investigated the effects of solar flares on the lower ionosphere by setting up two radio waves receivers – one at Bharati, the Indian research station in Antarctica, and the other in Tripura. These two receivers received radio waves generated from a transmitter located in Australia.
During solar flares, the amplitude of radio signal increased with the increase in short solar x-ray flux intensity. This study could also be utilized to infer daytime electron density change in the polar ionosphere during solar flare events.
Small solar flares effects could be efficiently detected from Bharati region in Antarctica due to electrical conductivity of the sea water which is several orders of magnitude higher than the land surface.
1. Guha, A. et al. Space weather effects on lower ionosphere: first investigation from Bharati station during 34th Indian scientific expedition to Antarctica. Adv. Space. Res. 59, 2007-2018 (2017)