CO{sub 2} ({lambda}{sub m}=10.6 {mu}m) He-Ne ({lambda}{sub c}=633 nm) two-color laser interferometry for low and medium electron density measurements in the TJ-II Stellarator

Journal Article · Mon Nov 01 00:00:00 EST 2004 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1809283· OSTI ID:20644005

Acedo, Pablo; Lamela, Horacio; Sanchez, Miguel; Estrada, Teresa; Sanchez, Joaquin ^[1]

---

1. Departamento de Tecnologia Electronica. Universidad Carlos III de Madrid, Avda. de la Universidad 30, Leganes 28911 Madrid (Spain)

In this article we describe the setup, installation, calibration, and operation of the two-color (CO{sub 2}-HeNe) laser heterodyne interferometer installed in the TJ-II Stellarator. This diagnostic has been routinely working during the last TJ-II experimental campaign (Autumn 2003) in low-density [electron cyclotron resonance (ECRH) heated, n{sub e} congruent with 10{sup 19} m{sup -3}] and medium density [neutral beam injection (NBI) heated, n{sub e} congruent with 5x10{sup 19} m{sup -3}] plasmas with line integral error better than 2x10{sup 17} m{sup -2}. This work demonstrates the possibility of using low-cost two wavelength laser interferometric diagnostics to measure low and medium-density plasmas instead of the complicated far infrared (FIR) interferometric systems that also suffer from fringe-jumps errors. The issues of low sensitivity to plasma density and mechanical vibration subtraction typical of these laser interferometers are solved through proper calibration of the interferometric system in the machine. First results on NBI heated plasmas measured by the laser interferometric system in the Stellarator TJ-II will be shown.

• OSTI ID: 20644005
• Journal Information: Review of Scientific Instruments, Vol. 75, Issue 11; Other Information: DOI: 10.1063/1.1809283; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION HEATING
CALIBRATION
CARBON DIOXIDE LASERS
CYCLOTRON RESONANCE
ECR HEATING
ELECTRON DENSITY
HELIUM-NEON LASERS
INTERFEROMETERS
INTERFEROMETRY
PLASMA BEAM INJECTION
PLASMA CONFINEMENT
PLASMA DENSITY
PLASMA DIAGNOSTICS
RF SYSTEMS
STELLARATORS
THERMONUCLEAR REACTORS