The enhanced soliton propagation and energy transfer in the coupled drift wave and energetic-particle-induced geodesic acoustic mode system

TL;DR

This paper investigates how the nonlinear interaction between drift waves and energetic-particle-induced geodesic acoustic modes enhances soliton propagation and energy transfer, revealing the regulation of drift waves by EGAM in plasma turbulence.

Contribution

It introduces a fully nonlinear coupled DW-EGAM model and explores the effects of linear EGAM drive and amplitude on turbulence evolution and energy transfer.

Findings

Linear EGAM drive enhances soliton propagation.

Energy transfer from DW to EGAM is always observed.

Conservation laws, including energy conservation, are derived.

Abstract

The evolution of the coupled drift wave (DW) and energetic-particle-induced geodesic acoustic mode (EGAM) nonlinear system is investigated using the fully nonlinear coupled DW-EGAM two-field equations, with emphasis on the turbulence spreading in the form of soliton and the nonlinear energy transfer between DW and EGAM. Four scenarios with different combinations of EGAM initial amplitudes and linear EGAM growth rates are designed to delineate the effects of linear EGAM drive and finite EGAM amplitude on DW nonlinear dynamic evolution. In presence of the linear EPs drive, the soliton propagation is enhanced, due to the generation of small radial scale structures. Two conservation laws of the nonlinear system are derived, including the energy conservation law. It is found that the energy of DW always decreases and that of EGAM always increases, leading to regulation of DW by EGAM.