Electrostatic ion cyclotron wave dispersion relation in a steady-state toroidal plasma

Electrostatic ion cyclotron wave dispersion relation has been studied in the experiment THORELLO, a steady-state magnetized toroidal plasma, produced in different neutral gases by hot-filament electron emission and acceleration by a bias voltage. Electron temperature and density, evaluated by Langmuir probes, are of the order of 5eV and 1010 cm−3, respectively. The maximum toroidal magnetic field on the axis is about 2kG. The waves are excited by a pair of thin metallic blades, fed with opposite phase by a low power (<10 W) RF signal, and detected by a movable RF probe. An interferometric method allows the evaluation of the perpendicular wave number, for any given frequency. The fit of experimental data with theoretical curves gives the possibility to evaluate the order of magnitude of the ion temperature.