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DOE OSTI · 3007751

Toroidal Alfven Wave Coupling (Nonlinear Wave-Wave Interactions) on DIII-D

Koepke, Mark [West Virginia Univ., Morgantown, WV (United States)]
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Abstract

Connect DIII-D physics with space plasma phenomena. In this case of using the toroidal Alfvén eigenmodes and frequency-chirping Reversed-Shear Alfvén eignmodes in DIII-D, we will document how the nonlinear interactions among dipolar Kinetic Alfvén Wave eigenmodes in space plasmas may determine saturation levels of these fluctuations. We seek evidence of nonlinear energy transfer and wave-wave coupling during 3-wave interactions mediated by a much lower-frequency mode. In FY2019, we found evidence of nonlinear “wave-wave” interactions in 175 relevant shots of archival DIII-D data. Toroidal mode number was identified and spectrograms were produced from each shot’s Mirnov coil data. Bispectral analysis was performed using a preliminary version of a new user friendly code derived from a 1995 M.S. thesis at WVU. These results formed a part of a May 2019 M.S. thesis at WVU.

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Koepke, Mark [West Virginia Univ., Morgantown, WV (United States)]. 2025-12-07. Toroidal Alfven Wave Coupling (Nonlinear Wave-Wave Interactions) on DIII-D. https://doi.org/10.2172/3007751

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