Publication Date:
2023-07-10
Description:
The Sun is the dominant energy source for ionizing atmospheric material and energizing a fraction of it to energies above the gravitational binding energy. Maggiolo et al. (2022) recently showed that, for current conditions, the solar wind energy dissipated in the Earth’s upper atmosphere is higher than it would be if the Earth were not magnetized. Indeed, despite shielding the atmosphere from the solar wind, the Earth’s magnetosphere has a much larger cross section with the solar wind than the planet itself. It thus dramatically increases the size of the interaction region between the solar wind and the planetary environment and thus the amount of solar wind energy that can potentially be diverted toward the upper atmosphere.In this study, we investigate the effect of the Earth’s magnetosphere on the solar wind energy dissipation in the atmosphere during the last 4 billion years, when the Sun was more active. The solar wind density and velocity were higher in the past which has two opposite effects. On the one hand, the Earth’s magnetosphere was more compressed by the higher solar wind pressure, reducing its cross section with the solar wind. On the other hand the solar wind energy flux density was higher. We use physical considerations and extrapolate current measurements to constrain the role of the Earth’s magnetosphere on the energy coupling between the solar wind and the upper atmosphere for such conditions.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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