Energy transfer from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves

Xiaofei Shi; Xin An; Vassilis Angelopoulos

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arXiv · 2509.19763

Energy transfer from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves

Xiaofei Shi·Xin An·Vassilis Angelopoulos

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Abstract

Large-amplitude slow-mode waves are commonly observed near Earth's magnetopause. Recent observations show that these waves can occur simultaneously with kinetic-scale ion acoustic waves. The amplitude of the ion acoustic waves is enhanced near the magnetic field peaks of the slow-mode wave, suggesting that the slow-mode waves may drive the generation of ion acoustic waves. To test this hypothesis, we conduct a hybrid simulation using observation-based parameters. The simulation results demonstrate that large-amplitude slow-mode waves generate counter-streaming ion beams, which in turn excite ion acoustic waves and relax the ion beams. Our study reveals a clear energy transfer channel from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves.

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Xiaofei Shi, Xin An, Vassilis Angelopoulos. 2025-09-24. Energy transfer from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves. https://arxiv.org/abs/2509.19763

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