Open AccessEquatorial night-time F-region zonal electric fields
Author(s) -
Sridhar Hari,
B. V. Krishna Murthy
Publication year - 1995
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-995-0871-8
Subject(s) - sunset , ionosonde , geology , f region , electric field , geodesy , ionosphere , magnetic dip , local time , atmospheric sciences , geophysics , electron density , physics , electron , mathematics , statistics , quantum mechanics , astronomy
Night-time F-region vertical\udelectrodynamic drifts at the magnetic equatorial station, Trivandrum are\udobtained for a period of 2 years, 1989 and 1990 (corresponding to solar cycle\udmaximum epoch), using ionosonde h'F data. The seasonal\udvariation of the vertical drift is found to be associated with the longitudinal\udgradients of the thermospheric zonal wind. Further, the seasonal variation of\udthe prereversal enhancement of the vertical drift is associated with the time\uddifference between the sunset times of the conjugate E-regions (magnetic\udfield line linked to F-region) which is indicative of the longitudinal\udgradients of the conductivity (of the E-region). The vertical drifts and\udthe causative zonal electric fields at Trivandrum are compared with those at\udJicamarca and F-region zonal electric field models. It is seen that the\udnight-time downward drift (as also the causative westward electric field) at\udJicamarca is greater than that at Trivandrum. The prereversal enhancement of the\uddrift is greater at Jicamarca than at Trivandrum during the summer and the\udequinoxes, whereas during the winter the opposite is the case