Excitation of the auroral green line by dissociative recombination of the oxygen molecular ion: Analysis of two rocket experiments

Abstract

Analysis from photometric and electron flux data obtained during two sounding rocket auroral experiments has yielded volume emission rates for the Na 2 +(0-0) First Negative Band and the OI( 1S− 1D) green line among other emission features. It is shown that excitation of the green line by electrons would require a cross section an order of magnitude larger than expected. From a calculation of the O 2 + production rate it is shown that dissociative recombination can account for the entire green line emission if one fifth of all O 2 + recombinations excite the 1S state. This is the laboratory measured value. Analysis also shows that this mechanism can describe the relative variation of λ3914 and λ5577 in time varying auroras.