Application of the Zeeman patterns to the measurement of local neutral behaviour in the edge plasma of TRIAM-1M tokamak

Plasma and Fusion Research

Shikama

Sawada

et al. 2011

We develop a collisional-radiative model for calculating the velocity distributions of excited hydrogen atoms. In the model, the velocity distributions are approximated using linear combinations of several basis functions which are treated as discrete velocity states, and only charge exchange collisions with proton are considered as velocity changing collisions. The populations in the velocity and excited states are calculated under an assumption of a quasi-stationary state. With the model we derive the velocity distribution of the ground state atoms from that of excited atoms in the n = 3 level observed for an LHD plasma, where n is the principal quantum number. The mean kinetic energy of the ground state atoms is estimated to be 5.6 eV, which is 0.05 eV less than that of the n = 3 atoms.

Section: Introductionsupporting

confidence: 66%

A Collisional-Radiative Model for Hydrogen Atom Including Velocity Changing Collisions

Plasma and Fusion Research

Shikama

Sawada

et al. 2011

“…1,2 Spectroscopic diagnostics of the dynamics of the neutral hydrogen ͑or deuterium͒ has been proposed by many authors. [3][4][5][6][7] From the observation of the line shape of the hydrogen Balmer-␣ emission from large helical device 3 ͑LHD͒ and Torus of Research Institute for Applied Mechanics ͑TRIAM-1M͒, 4 the emission locations of the atomic hydrogen in the peripheral region were determined from the Zeeman effect, together with the flow velocity and the temperature estimated from the Doppler effect. Regarding the molecular hydrogen, the Fulcher-␣ band spectra were measured for TRIAM-1M, and then the emission locations and the rotational and vibrational temperatures of hydrogen molecules were determined 5 with a similar analysis to that of the hydrogen Balmer-␣ spectra.…”

Section: Introductionmentioning

confidence: 99%

“…Regarding the molecular hydrogen, the Fulcher-␣ band spectra were measured for TRIAM-1M, and then the emission locations and the rotational and vibrational temperatures of hydrogen molecules were determined 5 with a similar analysis to that of the hydrogen Balmer-␣ spectra. 3,4 A simultaneous measurement of the line shapes of these spectra may provide the information about the neutral hydrogen transport as well as the dissociative dynamics of the molecules in the peripheral region.…”

Section: Introductionmentioning

confidence: 99%

Development of multiwavelength-range fine-resolution spectrometer for hydrogen emissions and its application to large helical device periphery plasmas

Review of Scientific Instruments

Mizushiri

Nishioka

et al. 2010

Self Cite

We developed a spectrometer specialized for simultaneous observation of the hydrogen Balmer-␣, -␤, -␥ lines and the Fulcher-␣ vЈ = vЉ = 2 rovibronic transition band. The spectrometer was optimized for the light input coupled by nine optical fibers having 400 m core diameters. The spectral resolutions were 0.02-0.03 nm for these wavelength ranges at the entrance slit width of 20 m. The polarization resolved spectra of these emissions from the peripheral region of large helical device ͑LHD͒ plasmas were measured simultaneously and showed the polarization dependence coming from the magnetic field in the LHD plasma.

“…From molecular line ratios, the rotational and vibrational temperatures, which are related to the background gas temperature, have been determined [8,9]. On the other hand, spatially resolved emission intensities and velocities of hydrogen atoms and molecules have been determined with a technique based on the Zeeman patterns appeared in the emission line shapes by several groups [8,10,11].…”

Section: Introductionmentioning

confidence: 99%

Development of Multi-Wavelength-Range High-Resolution Spectrometer for Hydrogen Atomic and Molecular Emission Lines

Plasma and Fusion Research

Shikama

Iwamae

et al. 2010

We have developed a spectrometer specialized for a simultaneous high-resolution measurement of emission spectra of the hydrogen atomic Balmer-α, -β, -γ lines and molecular Fulcher-α (v = v = 0) and (v = v = 2) ro-vibronic bands, where v and v is the vibrational quantum number. The instrumental widths for the respective wavelength ranges are 0.008, 0.009, 0.010, 0.008, and 0.007 nm. We apply the spectrometer to the observation of emissions from a LHD plasma. The observed profiles of these emission lines and bands show polarization dependence. The absolute intensities of these emissions are also estimated.