Effect of Solar Flares as determined from VLF transmitter signals

The amplitude variation of NWC signals (f= 19.8 kHz) has been monitored at Agra (Geographic Lat. 27.20 N, Long. 780E), India since March, 2011. The data have been analyzed for a large M1 classes solar flares occurred on 08/03/11.The results show that there occurred large fluctuations in the amplitude during the occurrence of the solar flares. The data have been compared with those corresponding to one day before and one day after the day of solar flares and the effect of the solar flare is confirmed. The detailed study of the magnitude of the amplitude fluctuations show that hard X-rays (1-8 วบ) are responsible for causing electron density variations in the D- region of the ionosphere which result into the fluctuation of signal amplitude. The effect of lightning, earthquakes and magnetic storm are also examined. In Fig.3 below the fluctuations in the amplitude of the signal correlating with the solar flares can be seen easily.

Fig.3: Daytime amplitude variation of NWC signal occurred on 08/03/11

Last Updated on July 1, 2011