  Collisionless geodesic acoustic modes in tokamaks being supersonic for large
"safety factor" q, the CGL (G. Chew, M. Goldberger, F. Low, 1956)1
double-adiabatic fluid closure is applied to formulate a theory for these
modes. The basic linear normal mode is obtained. External means to drive these
modes at resonance, as has been proposed earlier, are explored. The external
drivers considered include external magnetic forces to effect flux surface
displacements, as well as non-axisymmetric ion heating. Finally, the damping of
these modes from collisional magnetic pumping is investigated using a model set
of CGL collision-corrected equations.
