Characterization of temperature profiles in the outer region of RFX-mod.

The onset of helical states has been shown to strongly affect the transport properties and the plasma performance of both the core region (|R − R0|/a ≲ 0.5) and the plasma edge (|R − R0|/a ≳ 0.95) in the RFX-mod reversed field pinch experiment. Both regions have been widely investigated and a strong effort is still dedicated to deepening the comprehension of the phenomena affecting them. Conversely, the region bounded between the plasma core and the plasma edge (0.6 ≲ |R − R0|/a ≲ 0.95) has been poorly analyzed, despite the large plasma volume enclosed in this domain. Improvements in RFX-mod global plasma performance are thus closely linked to the identification of the physical mechanisms occurring in this region, referred to as the outer region. A specifically conceived method of analysis, which gathers together data from a Thomson scattering system and two edge temperature diagnostics, allows the study of the entire temperature profile of RFX-mod. A statistical analysis performed on a large discharge database shows that the temperature profile in the central region of the plasma column is mainly established by the plasma current and the degree of stochasticity of the magnetic field. On the other hand, the temperature profile in the outer plasma region is found to vary with electron density and plasma equilibrium. [ABSTRACT FROM AUTHOR]