Direct measurements of ion composition with EISCAT in the high‐latitude <i>F</i>₁ region

Abstract

We present a method for obtaining O + relative abundance directly from the autocorrelation functions measured by EISCAT; no assumption is made regarding the temperatures. Results of O + relative abundance and temperatures obtained simultaneously are shown for a 20‐hour period on May 9, 1982, and the time variations of O + relative abundance are compared to previous work.