Derivation of Meteor Stream Radiants by Radio Reflexion Methods

SINCE October 1944 we have carried out investigations of the short duration scatter echoes observable in the neighbourhood of the E region of the ionosphere at frequencies well above the critical frequencies for either the normal or abnormal E layers. The general occurrence of such echoes was first reported by Appleton, Naismith and Ingram¹ in their observations during the Polar Year 1932-33. Schafer and Goodall², who worked in collaboration with Skellett³ in an investigation of meteors as a source of abnormal E region ionization, had also noted them as a specific feature of the Leonid shower of 1931. An adequate reference to subsequent research cannot be given in a brief communication; but the work has for the most part led to the view that the transient ionospheric echoes are caused by meteors (see, for example. Appleton⁴). Our experiments have led us to confirm that the majority of scatter echoes must be of meteoric origin and are due to reflexions from meteor trains or streaks : these columns of ionized gas, caused by meteoric impact with the molecules of the upper atmosphere, present their maximum echoing areas when viewed at right angles to their length.