A Magnetospheric Source for Near‐Planet Whistler‐Mode Waves at Venus

The presence or absence of lightning in the atmosphere of Venus has important implications for atmospheric chemistry, potential chemical signatures of life, identifying volcanic activity, and quantifying potential hazards to future exploration missions. Prior studies have reported evidence both for and against the existence of Venusian lightning. One of the strongest pieces of evidence for Venusian lightning is the presence of whistler‐mode plasma waves in near‐Venus space. Similar waves are known to be generated by lightning at Earth. A recent study examined plasma wave data from the Parker Solar Probe spacecraft during a Venus flyby in 2021, concluding that the observed whistler mode waves had their Poynting flux directed toward Venus, consistent with wave production in the magnetosphere, and inconsistent with lightning generation. While highly suggestive, that study examined only a single brief flyby and was limited by data availability and the relatively high altitude of the flyby. The current study examines data from a Parker Solar Probe Venus flyby in 2024, which had improved data availability and reached lower altitudes compared to the 2021 flyby. Whistler‐mode waves are identified in the 2024 flyby data and found to be propagating toward Venus. The observation of planet‐directed whistler‐mode waves on multiple flybys widely spaced in time suggests that such waves may be a persistent feature of near‐Venus space. These results are consistent with a magnetospheric source of low‐altitude whistler mode waves at Venus and inconsistent with an atmospheric source such as lightning.