Observation of the externally excited fast magnetosonic wave via collective Thomson scattering

The fast magnetosonic wave externally excited in a Tokamak plasma is directly observed for the first time using nonperturbing collective scattering techniques. Eigenmode structure is compared with magnetic probe data. In addition, fast wave Langmuir probe measurements are also presented for a low density, low temperature plasma in the same toroidal cavity. In this case no eigenmode activity was observed due to toroidal damping. (author)