Study of solar flare-induced increases in TEC over Waltair

Faraday rotation data from the beacon satellite ETS-II obtained at Waltair (dip 20 N) for the period March-December 1978 were examined, and a total of 29 events of solar flare-induced increases in total electron content (TEC) were identified. It is observed that the sudden increase in TEC is found to vary from 1 to 7 percent over the preflare TEC value. The occurrence of the enhancement events were found to be maximum during the local afternoon hours. Further, there exists east-west and north-south heliographic symmetries in respect of the locations of the flares producing increases in TEC, with a preferential occurrence on the northwest quadrant of the solar disk.