Some unusual high dispersion whistler triplets recorded at a low L-value (L=1.17)

Abstract

A detailed analysis of the VLF data collected during January to December, 2003 at the low latitude station Jammu (geomag. lat., 22° 26′ N; L = 1.17) has yielded some unusual VLF events like whistler triplets of very high dispersion D ∼ 70 − 90 sec1/2. From the dispersion analysis of the whistler triplets, it is found that the individual whistlers of the triplets are one-hop high dispersion ducted whistlers having propagation path along higher and closely spaced L-values (L∼4.0) than the L-value of the recording station. The dispersion and occurrence characteristics of these high dispersion whistlers of the triplets are compared with those of the majority of low dispersion whistlers (D ∼ 30 − 40 sec1/2) recorded during the same period. Generation and propagation mechanisms are briefly discussed.