Day time whistlers observed at low latitude Varanasi ($$L = 1.078$$)

Abstract

We present results of the first time observations of whistlers during day time (sunrise) on 4th January 2017 at 01 UT ($$\hbox {UT} + 5.30 = \hbox {IST}$$) at Indian low latitude ground station Varanasi (geomag. lat. $$14{^{\circ }}55^\prime \hbox {N}$$, geomag. long. $$153{^{\circ }}54^\prime \hbox { E}$$, L.1.078). The main goal of analysis is to study the propagation characteristic of the observed whistlers during the day time (sunrise). These whistlers were observed during the quiet geomagnetic conditions (Dst-index = –8 nT). The dispersions of the observed whistlers are found between 11.16 and $$14.78\hbox { s}^{1/2}$$, which shows that the observed whistlers have propagated in the ducted mode and the whole propagation path of whistlers lies in the ionosphere. Their columnar ionospheric electron contents lie between 23.57 TECU and 39.44 TECU. The ionospheric parameters derived from whistler data at Varanasi compare well with other measurements made by other techniques.