Transequatorial VHF propagation through equatorial plasma bubbles

The support by the nighttime equatorial ionosphere of radio wave propagation at frequencies exceeding SO MHz is explained in terms of guiding along field-aligned tubes of depleted ionization resulting from the postsunset creation of equatorial plasma bubbles. By using the observed and theoretical properties of these bubbles, and considering in a numerical fashion a large ensemble of model bubbles, it is possible to reproduce many of the observed characteristics of transequatorial propagation at VHF.