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Ionospheric Sciences

Effects of Solar Eclipse on VLF Signal

A Solar Eclipse provides us an exciting opportunity to study the Very Low Frequency (3 to 30 kHz) propagation effects under a controlled experimental condition where the extreme ultraviolet and the X-rays from the sun are totally blocked by the moon. So far we have studied three Solar eclipses in Indian sub continent and beyond using multi-station VLF campaign.

Total Solar Eclipse, July 22, 2009

The data from 4 h to 20 h (IST) at (a) Kathmandu (b) Malda, (c) Khukurdaha, (d) Raiganj, (e) Salt Lake and (f) Pune (right). The blue curves represent the normal diurnal behavior (average of the day before and after the eclipse) at different places and the red curves represent the diurnal behavior on solar eclipse day at those places (see Chakrabarti et al., 2012, JASTP).

Annular Solar Eclipse, January 15, 2010:


The normalised variation of NWC (19.8 kHz) signal amplitude (left) before, on and after the eclipse day (15th).

Our Published Papers related to Solar eclipses:

Chakrabarti, S. K., Mondal, S. K., Sasmal, S. Pal S. et al.,"VLF signals in summer and winter in the Indian sub-continent using multi-station campaigns", 2012, Indian Journal of Physics 86 (5), 323-334, [Download PDF]

Pal, S., Chakrabarti, S.K., Mondal, S.K. et al., "Modeling of sub-ionospheric VLF signal perturbations associated with total solar eclipse, 2009 in Indian subcontinent",2012, Advances in Space Research 50, 196-204. [Download PDF]

Pal, S., Maji, S.K., Chakrabarti, S.K.,"First ever VLF monitoring of the lunar occultation of a solar flare during the 2010 annular solar eclipse and its effects on the D-region electron density profile",2012, Planetary and Space Science 73, 310-317 [Download PDF]

Chakraborty S., Palit S., Ray S., Chakrabarti S. K. et al."Modeling of the lower ionospheric response and VLF signal modulation during a total solar eclipse using ionospheric chemistry and LWPC",2016, Astrophysics and Space Science 361,72, 15 [Download PDF]

Maji, S. K. Chakrabarti S.K., Mondal, S.K.,"Unique Observation of a Solar Flare by Lunar Occultation During the 2010 Annular Solar Eclipse Through Ionospheric Disturbances of VLF Signals", 2012, Earth, moon and planets Etc. [Download PDF]

Pal, S., Chakraborty S., Chakrabarti S. K.,"On the use of Very Low Frequency transmitter data for remote sensing of atmospheric gravity and planetary waves", 2015, Advances in Space Research 55, 1190–1198 [Download PDF]

We have a plan to study the inospheric effects of upcoming total solar eclipse of August 21, 2017 visible in North America using our VLF/LF instruments.