The instability of the geodesic acoustic mode (GAM) in tokamak turbulence is analysed. It can be caused by dynamic shearing of the ambient turbulence by GAMs combined with the poloidal inhomogeneity of the turbulent flux. The dispersion relation is derived. The competition between the drive mechanism and the damping by turbulence viscosity is discussed. GAMs are more unstable for high safety factors.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Condensed Matter Physics