TJ-II:Interferometry: Difference between revisions
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The double wavelength heterodyne interferometer (CO<sub>2</sub>: 10.6 μm, NdYAG: 1.064 μm) | The double wavelength heterodyne interferometer (CO<sub>2</sub>: 10.6 μm, NdYAG: 1.064 μm) | ||
provides values of the plasma line integral density in scenarios with average densities ranging from a few times 10<sup>18</sup> m<sup>–3</sup> to more than 5×10<sup>19</sup> m<sup>–3</sup>. The results have been compared with those from the 2 mm (microwave) interferometer, obtaining an excellent agreement. Working with a final bandwidth of 4 kHz, a one pass line integral error level about ±2×10<sup>17</sup> m<sup>–2</sup> has been achieved. | provides values of the plasma line integral density in scenarios with average densities ranging from a few times 10<sup>18</sup> m<sup>–3</sup> to more than 5×10<sup>19</sup> m<sup>–3</sup>. The results have been compared with those from the 2 mm (microwave) interferometer, obtaining an excellent agreement. Working with a final bandwidth of 4 kHz, a one pass line integral error level about ±2×10<sup>17</sup> m<sup>–2</sup> has been achieved. | ||
<ref>[http://link.aip.org/link/?RSINAK/72/96/1 H. Lamela et al, ''Laser interferometric experiments for the TJ-II stellarator electron-density measurements'', Rev. Sci. Instrum. '''72''' | <ref>[http://link.aip.org/link/?RSINAK/72/96/1 H. Lamela et al, ''Laser interferometric experiments for the TJ-II stellarator electron-density measurements'', Rev. Sci. Instrum. '''72''' (2001) 96]</ref> | ||
<ref>[http://link.aip.org/link/?RSINAK/75/3414/1 M. Sánchez at al, ''High resolution CO<sub>2</sub> interferometry on the TJ-II stellarator by using an ADC-based phase meter'', Rev. Sci. Instrum. '''75''' | <ref>[http://link.aip.org/link/?RSINAK/75/3414/1 M. Sánchez at al, ''High resolution CO<sub>2</sub> interferometry on the TJ-II stellarator by using an ADC-based phase meter'', Rev. Sci. Instrum. '''75''' (2004) 3414]</ref> | ||
<ref>[http://link.aip.org/link/?RSINAK/75/4671/1 P. Acedo et al, ''CO<sub>2</sub> (λ<sub>m</sub> = 10.6 μm) He–Ne (λ<sub>c</sub> = 633 nm) two-color laser interferometry for low and medium electron density measurements in the TJ-II Stellarator'', Rev. Sci. Instrum. '''75''', 11 (2004) 4671]</ref> | <ref>[http://link.aip.org/link/?RSINAK/75/4671/1 P. Acedo et al, ''CO<sub>2</sub> (λ<sub>m</sub> = 10.6 μm) He–Ne (λ<sub>c</sub> = 633 nm) two-color laser interferometry for low and medium electron density measurements in the TJ-II Stellarator'', Rev. Sci. Instrum. '''75''', 11 (2004) 4671]</ref> | ||
The system is located in [[TJ-II:Sectors|sector]] B1. | The system is located in [[TJ-II:Sectors|sector]] B1. | ||
Revision as of 12:10, 13 October 2009
TJ-II has two interferometry systems for the measurement of the line-integrated density.
The Microwave interferometer
The diagnostic is located in sector B8. The probing beam has an inclination of 18.7º with respect to the vertical and a frequency of 140 GHz, corresponding to a wavelength of λ = 2.14 mm. The diagnostic provides a time trace of the line-integrated electron density (65536 points, sampling rate 100 kHz). The time trace is called 'Densidad2_' in the TJ-II database. The signal is less reliable for high densities (above 2-3 1019 m-3). This time trace is fundamental for machine operation.
Two-colour interferometer
The double wavelength heterodyne interferometer (CO2: 10.6 μm, NdYAG: 1.064 μm) provides values of the plasma line integral density in scenarios with average densities ranging from a few times 1018 m–3 to more than 5×1019 m–3. The results have been compared with those from the 2 mm (microwave) interferometer, obtaining an excellent agreement. Working with a final bandwidth of 4 kHz, a one pass line integral error level about ±2×1017 m–2 has been achieved. [1] [2] [3] The system is located in sector B1.
References
- ↑ H. Lamela et al, Laser interferometric experiments for the TJ-II stellarator electron-density measurements, Rev. Sci. Instrum. 72 (2001) 96
- ↑ M. Sánchez at al, High resolution CO2 interferometry on the TJ-II stellarator by using an ADC-based phase meter, Rev. Sci. Instrum. 75 (2004) 3414
- ↑ P. Acedo et al, CO2 (λm = 10.6 μm) He–Ne (λc = 633 nm) two-color laser interferometry for low and medium electron density measurements in the TJ-II Stellarator, Rev. Sci. Instrum. 75, 11 (2004) 4671