Measurements of Z{sub EFF} spatial profiles from bremsstrahlung emission in the visible and near infrared spectral region
- Associazione EURATOM-ENEA sulla Fusione, Centro Ricerche Frascati, C.P.65, 00044 Frascati, Rome (Italy)
Measurement of plasma radiation (i.e., breusstrahlung) in the infrared (IR) range ({lambda}=933, 978 nm), at six lines of sight from z={minus}20 cm to z=8 cm above the equatorial plane, using the detection system of the Frascati Tokamak Upgrade (FTU) Thomson scattering system (TSS) are reported. The agreement of IR with visible ({lambda}=540 nm) bremsstrahlung intensity {ital S}, [S=photons/(m{sup 2}srnms)] measurements is within 20{percent}{endash}30{percent} and depends upon the absolute calibration of both systems. The intensity is equal S(z)={l_angle}Z{sub eff}Gn{sup 2}/T{sub e}{sup 1/2}{r_angle}, where {l_angle}{center_dot}{r_angle} means average on a line of sight. For determining the Z{sub eff} the Gaunt factor(G) is needed, and analysis the Born{endash}Elwert formula is used. The Z{sub eff} spatial profiles (i.e., Z{sub eff}(r)), are determined using the plasma temperature (T{sub e}) and density (n{sub e}) measured by the TSS and the Abel inverted intensity profiles, determined using the plasma radiation S(z) measured from six horizontal chords. Z{sub eff}(r) behavior in a variety of FTU discharges is presented. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 451943
- Report Number(s):
- CONF-960543--
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 1 Vol. 68; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
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