RESEARCH UNIT: ISTP-Padova
WP LEADER: MARCO BARBISAN
The objective of this work package is to enhance the diagnostic capability of the RFX experiment by improving the measurement of the ion temperature profile. This is accomplished by injecting energetic neutrals into the plasma using a Diagnostic Neutral Beam Injector (DNBI) to probe the core region. When the probing neutrals collide with the thermal hydrogen (or deuterium), they transfer an electron, making some of the bulk ions neutral via charge exchange. The new neutral component in the plasma has the same energy content as the bulk ions. By analyzing the radiation emitted by these atoms spectrally, collective flows and ion thermal temperature profiles can be measured in the plasma.
This work package comprises two main activities:
It is crucial to have knowledge of the ion temperature gradient to characterize the underlying turbulence and estimate the frequency of Geo Acoustic Modes (GAMs), which are the high-frequency branch of the zonal flows. Furthermore, Charge Exchange Recombination Spectroscopy is the basis for Fast Ion D alpha detection. Furthermore, Neutral Particle Analyzers can intercept fast ions that have recombined into neutrals and escaped the magnetic confinement.