Observation of tweek atmospherics in Vietnamese low latitude region using a simple VLF receiver

This paper presents the characteristics of tweek occurrence captured at a low latitude station in Tay Nguyen University, Viet Nam (12.65°N; 108.02°E). About 2443 tweek atmospherics with different modes n = 1 - 8 obtained during the night in October, 2012 were analyzed to estimate the night-time reflection height of the Earth-Ionosphere waveguide (EIWG), the D-region equivalent electron density and the propagation distance from the causative lightning discharge to the receiving station. The results show that the tweeks from 2^nd mode to 4^th mode occurred more often than the tweeks with different modes and the mean reflection height increases with increase in mode number. In addition, the electron density of the D-region ionosphere varies in the range of 26.31 - 31.62 el/cm³ at the ionospheric reflection height of 78.91 - 89.07 km. About 71.2 % of the tweeks propagated distances between 1000 km and 6000 km in the EIWG to the recording station.