Open AccessCold-hot coupled waves in a flowing magnetized plasma
Author(s) -
Min Uk Lee,
JeongYoung Ji,
Gunsu Yun
Publication year - 2020
Publication title -
nuclear fusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.774
H-Index - 120
eISSN - 1741-4326
pISSN - 0029-5515
DOI - 10.1088/1741-4326/abb61a
Subject(s) - physics , dispersion relation , plasma , vlasov equation , phase velocity , wavenumber , mechanics , wavelength , distribution function , amplitude , zonal flow (plasma) , harmonics , dispersion (optics) , computational physics , wave propagation , classical mechanics , optics , tokamak , quantum mechanics , voltage
Nonlinear coupling of cold and hot waves in a flowing magnetized plasma is analyzed with the Vlasov equation. An analytical solution is obtained for cold waves of a small amplitude (weak flow) and a long wavelength. The distribution function is obtained by integrating the kinetic equation along a perturbed phase-space trajectory for a time-varying plasma flow. The kinetic description presents a generalized dispersion relation that involves resonances depending on cold and hot wave dispersions. Coherent fluid motion leads to radiation peaks in addition to the cyclotron harmonics, where the wavenumber of the cold wave determines the peak frequencies. The peaks appear narrow when the wave propagates perpendicular to the time-averaged flow while they become broad due to the Doppler effect when the wave propagates parallel to the flow. Fully kinetic particle-in-cell simulations corroborate the theoretical predictions. The dispersion relation and resulting wave spectra provide information about plasma parameters and flow properties.