Quasi-optical design for the cross-polarization scattering diagnostic on the HL-3 tokamak.
Rev Sci Instrum
; 95(5)2024 May 01.
Article
in En
| MEDLINE
| ID: mdl-38758767
ABSTRACT
As the plasma beta (ß) increases in high-performance tokamaks, electromagnetic turbulence becomes more significant, potentially constraining their operational range. To investigate this turbulence, a cross-polarization scattering (CPS) diagnostic system is being developed on the HL-3 tokamak for simultaneous measurements of density and magnetic fluctuations. In this work, a quasi-optical system has been designed and analyzed for the Q-band CPS diagnostic. The system includes a lens group for beam waist size optimization, a rotatable wire-grid polarizer for polarization adjustment, and a reflector group for measurement range regulation and system response enhancement. Laboratory tests demonstrated a beam radius of order 4 cm at the target measurement location (near the plasma pedestal), cross-polarization isolation exceeding 30 dB, and poloidal and toroidal angle adjustment ranges of ±40° and ±15°, respectively. These results verify the system's feasibility through laboratory evaluations. The quasi-optical system has been installed on the HL-3 tokamak during the 2023 experimental campaign to support the development of CPS diagnostics.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Rev Sci Instrum
Year:
2024
Document type:
Article
Affiliation country:
China