Parametric decay instability near the upper hybrid resonance in magnetically confined fusion plasmas. (11th August 2017)

• Record Type: Journal Article
• Authors: Hansen, S K; Nielsen, S K; Salewski, M; Stejner, M; Stober, J
• Other Names: collab.
• Is Part Of: Plasma physics and controlled fusion. Volume 59:Number 10(2017:Oct.)
• Publication Date: 2017-08-11
• Subjects: PDI -- UHR -- UH -- LH -- CTS -- ECRH -- electron Bernstein wave; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/aa7978
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: In this paper we investigate parametric decay of an electromagnetic pump wave into two electrostatic daughter waves, particularly an X-mode pump wave decaying into a warm upper hybrid wave (a limit of an electron Bernstein wave) and a warm lower hybrid wave. We describe the general theory of the above parametric decay instability (PDI), unifying earlier treatments, and show that it may occur in underdense and weakly overdense plasmas. The PDI theory is used to explain anomalous sidebands observed in collective Thomson scattering (CTS) spectra at the ASDEX Upgrade tokamak. The theory may also account for similar observations during CTS experiments in stellarators, as well as in some 1st harmonic electron cyclotron resonance and O-X-B heating experiments.