Non-thermal Escape in Venus Atmosphere

The three rocky planets of our Solar System, Earth, Venus, and Mars, each once had the potential to sustain habitable conditions, yet today only Earth remains habitable. A key factor governing planetary habitability is the ability to retain an atmosphere. At present, atmospheric loss from all three terrestrial planets is dominated by non-thermal escape processes driven by interactions between planetary atmospheres and the solar wind. In the absence of a strong intrinsic magnetic field, Venus is particularly vulnerable to such interactions.

In this presentation, I will focus on the role of non-thermal escape processes on present-day and early Venus, with particular emphasis on ion pickup. Neutral atmospheric species ionized by solar UV radiation and charge exchange are continually picked up by the magnetized solar wind, resulting in the loss of planetary volatiles. While present-day escape rates are too low to substantially cause thinning of atmosphere, these processes were likely far more efficient under the enhanced solar activity conditions of the early Solar System. I aim to explore how non-thermal escape drives the long-term evolution of Venus and contributed to the development of its present CO₂-dominated atmosphere. The possible existence of an early Venusian magnetic dynamo and its implications on non-thermal escape may also provide context for Venus as an analogue for early Earth and rocky exoplanets.