Microturbulence in helical and axisymmetric reversed field pinch plasmas

In the reversed field pinch device RFX-mod (Padova, Italy), good confinement properties are achieved when the magnetic surfaces become helical. This condition causes on overall reduction of the magnetic chaos, but, at the same time, creates the physical conditions mostly favoring the onset of electrostatic/electromagnetic turbulence, e.g., the occurrence of large pressure gradients. In this contribution we review some recent findings in this field, focusing on the 3D features of the helical magnetic field, with the aim to describe its distinct properties compared to an axisymmetric plasma. We will discuss, in particular, the results on ion temperature gradient turbulence, and the effect of a finite plasma beta on electromagnetic instabilities and turbulence.