منابع مشابه
Radial localization of toroidicity-induced Alfvén eigenmodes.
Linear gyrokinetic simulation of fusion plasmas finds a radial localization of the toroidal Alfvén eigenmodes (TAEs) due to the nonperturbative energetic particle (EP) contribution. The EP-driven TAE has a radial mode width much smaller than that predicted by the magnetohydrodynamic theory. The TAE radial position stays around the strongest EP pressure gradients when the EP profile evolves. The...
متن کاملObservation of odd toroidal Alfvén eigenmodes.
Experimental evidence is presented for the existence of the theoretically predicted odd toroidicity induced Alfvén eigenmode (TAE) from the simultaneous appearance of odd and even TAEs in a normal shear discharge of the joint European torus. The modes are observed in low central magnetic shear plasmas created by injecting lower hybrid current drive. A fast ion population was created by applying...
متن کاملImproved Particle Confinement Mode in the H-1 Heliac Plasma.
The first experimental observation of the sudden transition to the improved particle confinement mode in the H-1 heliac is reported and shows a clear dependence on magnetic configuration. In a lowtemperature plasma a transition to improved confinement followed by a twofold increase in the electron density is observed when the magnetic field exceeds a critical value Bcr . At B ø Bcr the transiti...
متن کاملObservations of Alfvénic MHD Activity in the H-1 Heliac
Magnetic configuration scans in the range 1.1 < ι0 < 1.5 in the H-1 flexible heliac have shown a detailed rotational transform dependence of plasma density and fluctuation spectra. Poloidal Mirnov arrays reveal magnetic fluctuations in the range 1-200kHz in plasma produced by RF heating in H, D and He mixtures ranging from highly coherent, often multi-frequency, to broad band. Both positive (st...
متن کاملNonlinear frequency oscillation of Alfvén eigenmodes in fusion plasmas.
A nonlinear oscillation of frequency and amplitude is found by massively parallel gyrokinetic simulations of Alfvén eigenmodes excited by energetic particles in toroidal plasmas. The fast and repetitive frequency chirping is induced by the evolution of coherent structures in the phase space. The dynamics of the coherent structures is controlled by the competition between the phase-space island ...
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ژورنال
عنوان ژورنال: Plasma Physics and Controlled Fusion
سال: 2017
ISSN: 0741-3335,1361-6587
DOI: 10.1088/1361-6587/aa8bdf