Middle and High Latitude Whistlers Observed Simultaneously in a Low Latitude Station at Agra

The characteristics of very high dispersion (D ∼ 54-70 sec1/2) whistlers recorded simultaneously in a low latitude ground station at Agra (geomag. lat. 17°1'N, L =1.15) during the night-time observation on 2 April, 1979 are studied and their propagation paths are determined using the curve fitting technique. The results show that some of these whistlers are high latitude whistlers which propagated along the magnetic field line of L = 3.6 while the others are one hop and three hop mid-latitude whistlers which propagated along the field lines between L = 1.9 to 2.5. Some of these whistlers are recorded simultaneously in our ground station. The dispersion and occurrence characteristics of these high dispersion whistlers are compared with those of the majority of relatively low dispersion ducted whistlers (D ∼ 30-35 sec1/2) which were recorded in our station during the same period of observation and then we discuss the propagation characteristics of high dispersion whistlers in terms of nonducted Pro-Longitudinal mode (PL mode) of propagation.