A theoretical explanation of intensities of storm-time VLF hiss emissions observed at low latitudes

Abstract

For known plasma parameters and considering quasi-linear electron cyclotron resonance instability and incoherent Cerenkov radiation process, the intensities of intense storm-time VLF hiss emissions, observed in the low latitude ground stations of Japan, are explained. Based on the intensity calculations in low latitude equatorial plane, which are inconsistent

with the observed intensities, the local generations by either of the above two mechanisms are ruled out. It is suggested that the emissions are due to mechanism of quasi-linear electron cyclotron resonance instability in the equatorial plane at <i>L</i><span style="font-size:12.0pt;font-family:" cambria="" math","serif";="" mso-bidi-font-family:"times="" new="" roman""="" lang="EN-IN">≃ 3.6 by -5 keV electrons which drift eastward from higher latitudes and enter the ionosphere at a latitude higher than that of

Moshiri (<i>L </i><span style="font-size:12.0pt;font-family:" cambria="" math","serif";="" mso-bidi-font-family:"times="" new="" roman""="" lang="EN-IN">≃1.6). These then propagate towards the observer in earth-ionosphere wave-guide mode.

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