Particle-in-cell simulations of parametric decay instabilities at the upper hybrid layer of fusion plasmas to determine their primary threshold

Mads Givskov Senstius*, Stefan Kragh Nielsen, R. G. Vann, Søren Kjer Hansen

*Corresponding author for this work

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Parametric decay instabilities (PDIs) are nonlinear processes by which energy from a strong pump wave may be directed into other waves at other frequencies, in particular natural modes of the medium, provided that energy and momentum are conserved. The particle-in-cell (PIC) code EPOCH is used to simulate PDIs in a magnetically confined fusion plasma converting a 105 GHz microwave X-mode pump wave into electrostatic daughter waves at the upper hybrid (UH) layer. Modes associated with the PDIs as well as a linearly converted electron Bernstein wave (EBW) are identified in f- and k-space. The PDI daughter modes are found to agree with experimental observations from ASDEX Upgrade as well as with analytical predictions, showing a nonlinear increase in power above a predicted threshold.
Original languageEnglish
Article number025010
JournalPlasma Physics and Controlled Fusion
Issue number2
Number of pages13
Publication statusPublished - 2020


  • Parametric decay instabilities
  • Particle in cell
  • Upper hybrid layer
  • Electron Bernstein waves

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