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arXiv · 2507.02042

Langmuir Wave Excitation in Solar-wind Magnetic Holes

Jingting Liu·Daniel Verscharen·Jesse Coburn·Georgios Nicolaou·Xiangyu Wu·Wence Jiang·Oreste Pezzi·Francesco Pucci·Matteo Zuin·Christopher J. Owen·Hamish Reid
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Abstract

Magnetic holes are structures commonly observed in various space plasma environments throughout the solar system, including the solar wind. These structures are characterized by a localized decrease in magnetic field strength, coincident with an increase in plasma density. Previous observational studies in the solar wind link the presence of Langmuir waves to magnetic holes, suggesting a strong correlation between these phenomena. We develop a model based on magnetic-moment conservation and its violation to explain the excitation of Langmuir waves in magnetic holes. Our model illustrates that magnetic holes induce changes in the electron velocity distribution function that emit electrostatic Langmuir waves due to the bump-on-tail instability. Using data from the Solar Orbiter spacecraft, we provide a comprehensive analysis of this process and test our predictions with observations. The consistency between the model and observations indicates that our proposed process is a viable mechanism for producing Langmuir waves in magnetic holes in the solar wind.

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Jingting Liu, Daniel Verscharen, Jesse Coburn, Georgios Nicolaou, Xiangyu Wu, Wence Jiang, Oreste Pezzi, Francesco Pucci, Matteo Zuin, Christopher J. Owen, Hamish Reid. 2025-07-02. Langmuir Wave Excitation in Solar-wind Magnetic Holes. https://arxiv.org/abs/2507.02042

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