First optical observations of interhemispheric electron reflections within pulsating aurora

A case study of a pulsating auroral event imaged optically at high time resolution presents direct observational evidence in agreement with the interhemispheric electron bouncing predicted by the SuperThermal Electron Transport model. Pulsation-on times are identified and subsequent equally spaced fainter pulsations are also noted and can be explained by a portion/percentage of the primary precipitating electrons reflecting upward from the ionosphere, traveling to the opposite hemisphere and reflecting upward again. The high time resolution of these data, combined with the short duration of the pulsation-on time (approximate to 1s) and the relatively long spacing between pulsations (approximate to 6 to 9s) made it possible to observe the faint optical pulses caused by the reflected electrons coming from the opposite hemisphere. Plain Language Summary This is the first time we show evidence that a certain type of aurora is caused by electrons bouncing back and forth between the two hemispheres. This means that these electrons are responsible for some of the total light in the aurora, a possibility that has largely been ignored in theoretical models.