Transequatorial VHF propagation through equatorial plasma bubbles


  • M. L. Heron,

  • L. F. McNamara


The support by the nighttime equatorial ionosphere of radio wave propagation at frequencies exceeding 50 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.