In a world increasingly facing new challenges at the forefront of plasma scientific research and technological innovation, CNR and ISTP pledge progress and achieve an impact in the integration of research into societal practices and policy
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In a world increasingly facing new challenges at the forefront of plasma scientific research and technological innovation, CNR and ISTP pledge progress and achieve an impact in the integration of research into societal practices and policy
RESEARCH UNIT: ISTP-Padova
WP LEADER: LORELLA CARRARO
To improve power balance, heat transport analyses and turbulence effect studies, activities of development and strenghtening of RFX-mod2 diagnostics for ion temperature and fast ion dynamics, for enhanced electron temperature profile time evolution measurements, for bolometry diagnostic update are proposed.
In particular the Thomson Scattering diagnostic will be updated with one new laser, a new set of waveform digitizers, and an enhanced acquisition system, for a high time resolution (500 Hz) Te radial profile measurement in the core (up to r/a=0.9) and at the edge.
The SXR tomography capability will be extended with 3 vertical top port holes in one toroidal section for Te profile measurements with increased spatial resolution; the acquisition system will be replaced to match the increased number of channels; remote control of amplifier gains will be included.
To perform Power balance and heat transport analyses, the Tomography system will be enhanced. In particular, for Bolometry it is foreseen an increase of the time resolution up to 2 kHz (actual 500 Hz) and remote control of amplifier gains.
Ion temperature (Ti) profile is another key ingredient for a nuclear fusion device; for the RFX-mod plasmas the energy released during reconnection events, might be involved in ion heating. The design and procurement of a CNPA diagnostic for RFX-mod2 is proposed.
Expected outcomes of this development include:
SXR Te measurement extension and bolometry tomograpy update:
A critical issue in a reactor perspective is the understanding of the impurity behaviour, especially to avoid the impurity peaking. Soft X Rays (SXR) tomography allows MHD studies and fast evaluation of impurity profile behaviour (tens of kHz), allowing the study of plasma structure dynamics. Accurate measurements of SXR emissivity profiles time evolution is fundamental for impurity transport analysis, based on the simulation of the experimental emission pattern. SXR data can be also used to measure the Te profiles, with the double-foil (DF) ratio technique. Bolometric data, in conjunction with local energy balance calculation, allow to study the plasma power balance. The replacement of the obsolete amplification and acquisition system of the actual 3 bolometric cameras is proposed, to reach a time resolution of 2 kHz (now 500 Hz).
Thomson Scattering diagnostic enhancement:
New Laser for enhancement of Thomson Scattering core and edge Te profile along the equatorial diameter in 84 positions (up to r/a 0.85). The main goal is high repetition rate of measurements (one profile every 2 ms), very close to the time resolution of the Te profiles deduced from SXR measurements. The selected laser, of the type Nd:YAG, will produce fast burst of high energy (3 J or more) pulses. Te profiles in the external region of the plasma (r/a >0.8) will be measured with the same high time resolution of the core Thomson Scattering.
Compact Neutral Particle Analyzer (CNPA) diagnostics:
Neutral Particle analysis gives information on ion temperature and fast particle dynamics as it resolves the energy distribution of the neutral particles, which are produced by charge-exchange reactions with ions and leave the plasma. The Compact Neutral Particle Analyzer diagnostics will give fundamental information about the ion heating phenomena and fast particle confinement and behavior in the various magnetic configurations. The proposed diagnostics allows measuring and discriminating the Hydrogen and Deuterium atom fluxes with good energy resolution in the energy range spanning from 0.66 to 80 keV.
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