Registration Number
0226U004690,
(0121U110703)
, R & D reports
Title
Processes associated with superthermal ions in tokamaks and stellarators
popup.stage_title
Модель нелінійної динаміки МГД мод. Структура резонансів швидких магніто-звукових мод (ШММ).
Head
Kolesnychenko Yaroslav І., Доктор фізико-математичних наук
Registration Date
04-11-2026
Organization
Institute of Nuclear Research of the National Academy of Sciences of Ukraine
popup.description1
The aim of the proposed work is development of а theory of fusion plasmas, interpretation of experiments, predictive calculations, search of ways to improve plasma performance in fusion devices. Specific tasks of the work are as follows: (i) To find amplitudes of the electromagnetic field and fraction of the energy lost by superthermal ions in nonlinear stage of instabilities driven by Fast Magnetoacoustic Modes (FMM) with frequencies above the ion gyrofrequency; (ii) To study structure of high-frequency FMM and their destabilization by superthermal ions; (iii) To clarify the influence of the Spatial Channeling (SC) of the energy and momentum of fast ions on the structure of MHD modes and the energy transfer across the magnetic field by these modes; (iv) To understand reasons of sharp changes of the frequency of MHD-activity in plasmas with high fraction of energetic ions in hybrid discharges of tokamaks; (v) To identify mechanism of mitigation of turbulent heat fluxes by fast ions, which was observed in both numerical and real experiments; (vi) To develop a numerical code for calculation of the 4-D evolution of the fast-ion distribution function in the presence of sawtooth perturbations. (vii) To investigate possibility to improve plasma performance in specific fusion devices by employing collective processes.
popup.description2
A theory of spatial momentum transfer by collective processes in thermonuclear plasma has been constructed. It is shown that eigen oscillations excited by energetic ions can affect the inhomogeneous rotation of the plasma. It is shown that linearly stable toroidal Alfvén modes (TAE) can be excited nonlinearly by ion drift-temperature turbulence. The excitation mechanism is inverse Compton scattering by energetic ions. An analysis of discharges in a recent series of experiments on the JET tokamak, where TAE mode excitation was observed, was performed. A change in the plasma rotation frequency was observed upon excitation of TAE modes. The possibility of the existence of an island structure of the magnetic field for paramagnetic pinches of the kink-mode type m=1, n=0 in the approximation of a force-free axisymmetric magnetic configuration is shown.
Product Description
popup.authors
Vadym V. Lutsenko
Viktor S. Marchenko
Yurii V. Yakovenko
Oleh S. Burdo
Viktor Y. Goloborod’ko
Sviatoslav M. Reznyk
Anton V. Tykhyi
Anatolii A. Huryn
Tymofii S. Rudenko
popup.nrat_date
2026-11-04
