Recent research challenges the conventional understanding of the enigmatic STEVE and picket fence phenomena, proposing a novel mechanism distinct from auroras. Traditionally, auroras are attributed to the precipitation of charged solar particles into Earth’s upper atmosphere along magnetic field lines. However, STEVE and the picket fence exhibit unique characteristics that defy this explanation.
This study, led by physicist Claire Gasque, suggests that STEVE and the picket fence are produced by parallel electric fields rather than magnetic fields. These electric fields accelerate electrons in the upper atmosphere, causing them to excite atmospheric atoms and molecules, resulting in the observed emission. This mechanism operates at lower latitudes than traditional auroral production, implying a distinct physical process.
Gasque’s findings are based on spectral analysis of the picket fence, which revealed a peculiar green hue absent of the blue emission typical of auroras. This suggests that the exciting electrons possess a specific energy range incompatible with the high-energy particles associated with auroras.
Furthermore, the study proposes that a similar electric field-driven mechanism may be responsible for the generation of STEVE. To validate these hypotheses, Gasque advocates for directly probing STEVE or the picket fence with in-situ measurements. However, the rarity of these phenomena necessitates targeting readily accessible alternatives, such as enhanced auroras – regions within auroras exhibiting similar spectral characteristics.
This research represents a significant step towards elucidating the enigmatic STEVE and picket fence phenomena. If confirmed, these findings will have profound implications for our understanding of Earth’s upper atmospheric dynamics, the magnetosphere’s role, and the energy exchange between Earth and the Sun.