Magnetic fluctuations, observed in the Alcator C-Mod experiment, are modelledvia the instability of microtearing modes with ratio ofpoloidal to toroidal mode number m/n = 4. These modes are predominantly electromagnetic in nature, although the electrostatic component is non-vanishing, are driven by the steeptemperature gradient at the plasma edge and are shown to have a relativelybroad spectrum for typical experimental parameters.
Fast Alfven eigenmodes in a cylindrical inhomogeneous plasma