Current carrying filaments in the L-mode, H-mode and ELMs in RFX-mod tokamak operation

The RFX-mod experiment is a fusion device designed to operate as a Reversed Field Pinch (RFP), with a major radius R= 2 m and a minor radius a = 0.459 m. Its high versatility recently allowed operating also as an ohmic tokamak allowing comparative studies between the two configurations in the same device. The device is equipped with a state of the art MHD mode feedback control system, providing a magnetic boundary effective control, by applying resonant or non-resonant magnetic perturbations (MP) both in RFP and in tokamak configurations. In the fusion community the application of MPs is widely studied as a promising tool to limit the impact of plasma filaments and ELMs on plasma facing components. An important issue is envisaged in the exploitation of the RFX-mod active control system for ELM mitigation studies. As a first step in this direction, this paper will focus on the most recent achievements in term of RFX-mod tokamak explored scenarios, which allowed the first investigation of the ohmic and edge biasing induced H-mode. Reproducible H-mode phases were obtained with insertable electrode negative biasing stimulation in shaped Single Null discharges, representing an unexplored scenario with this technique. Features of current carrying filaments in L-mode , Hmode and within ELM cycle are studied in details.