On electrostatic coupling in ICRH at the plasma edge

The mechanisms leading to a concomitant coupling of electrostatic (ES) waves in ion cyclotron range fast wave heating experiments are studied. Mode conversion at the lower hybrid resonance and direct coupling to ES waves due to the misalignment of the antenna Faraday shields are considered as sources of intense ES waves in the edge plasma. Ion acceleration by wave trapping is suggested as a mechanism that restricts the amplitude of the parasitic modes and creates energetic ions