Numerical description of mode coupled waves in inhomogeneous magnetized plasmas
Nagoya University Nagoya, Aichi, Japan
2 National Institute for Fusion ScienceToki, Gifu Japan
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Published online: 25 March 2019
Geometrical optics (GO) ray tracing has been widely used for a description of electron cyclotron resonance waves in inhomogeneous magnetized fusion plasmas. However, this reduced approach is not correct in suﬃcient low density plasmas with a sheared magnetic ﬁeld, where mode coupling between two electromagnetic-like cold plasma modes can occur. Here, we extend a ray tracing method based on the ﬁrst-order theory of extended geometrical optics (XGO), which captures mode coupled complex amplitude between O and X mode along the ray trajectory. In our approach, reference ray is calculated with ray equation to satisfy the lowest-order part of XGO theory and an evolution of complex amplitude proﬁle along the reference ray is calculated with partial diﬀerential equation derived from ﬁrst-order terms. Calculation results performed by extended ray tracing are in good agreement with 1D full wave analysis. By introducing second-order terms into our numerical approach, diﬀraction will be treated.
© The Authors, published by EDP Sciences, 2019
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