TORPEX is equipped with an extensive set of diagnostics, comprising approximately 200 probes, allowing a full reconstruction of plasma and turbulence properties across the entire device. Measurements of plasma parameters and of fluctuations (including wave dispersion relations and statistical properties) are performed primarily using electrostatic probes, in the Langmuir probe (operated in single, double, triple, and particle flux scheme) or in the Mach probe configurations, and magnetic probes disposed at different toroidal locations and covering almost the entire plasma poloidal cross-section.
Two 85-tip partially movable probe arrays named HEXTIP, placed at two toroidal locations, constitutes the workhorse for a high temporal resolution (250kHz) real space imaging of the density (from the ion saturation current) and floating potential dynamical evolution.
TORPEX is also equipped with a fast ion (10eV- 1keV) source, which can be installed directly inside the vacuum vessel. The source is based on a two grid accelerating system with a thermionic emitter. A miniaturized gridded energy analyzer measures fast ion energies and current density profiles across the entire poloidal cross section. Electrostatic probes are complemented by a fast imaging system, comprising a fast framing camera and an image intensifier, to monitor visible light fluctuations, up to 250kframes/s. Such system allows a fully non-perturbative reconstruction of plasma dynamics at different scales, with a spatial resolution as high as a few mm. The flexibility of the TORPEX device and its diagnostic suite, together with simulation tools, have allowed ground-breaking progress in the understanding of turbulence in the SMT configuration.