Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device

Abstract

We observe the Balmer-a, -b, and -c lines of hydrogen atoms and Q branches of the Fulcher-a band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 $ 20 eV, while the rotational temperature of molecules is $0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-a line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there. V C 2013 American Institute of Physics. [http://dx.

Anisotropy in Broad Component of H<i>α</i> Line in the Magnetospheric Device RT-1

“…Furthermore, the hot neutral temperature had anisotropy (T ⊥ > T || ). Even though the preceding studies already observed the hot neutral flow [15][16][17], the observation of the temperature anisotropy in hot neutrals is the very first. The dependencies of hot neutral temperature and anisotropy were consistent with ions.…”

“…The dependencies of hot neutral temperature and anisotropy were consistent with ions. Since hot neutrals emitting a broad component are mainly produced by charge exchange between neutrals and protons [17], the flow and the anisotropy were inherited from protons. Therefore, our observation is the evidence of proton temperature anisotropy in RT-1.…”

“…Broad component of Balmer lines has also been observed in labora- * Electronic address: kawazura@ppl.k.u-tokyo.ac.jp tory plasma [12][13][14]. In addition to narrow and broad components, the recent studies identified threefold (cold, warm and hot) Balmer lines [15][16][17]. The one-dimensional neutral particle transport model clarified that the hot component was generated by charge exchange with protons [17].…”

“…In addition to narrow and broad components, the recent studies identified threefold (cold, warm and hot) Balmer lines [15][16][17]. The one-dimensional neutral particle transport model clarified that the hot component was generated by charge exchange with protons [17]. Unlike in the case of astrophysical plasma, it is challenging to infer proton temperature via Doppler temperature of a broad component in laboratory.…”

Hydrogen Atomic and Molecular Emission Locations and Intensities in the LHD Edge Plasma Determined from Simultaneously Observed Polarization Spectra

“…For the purpose of further improving this technique, we recently demonstrated a method to observe several emission spectra of hydrogen atoms and molecules simultaneously with developing a multi-wavelength highresolution (MH) spectrometer [16,17]. From the observed Zeeman splits of the atomic and molecular lines, we have shown the difference of the atomic and molecular emission locations in the LHD [18]. In this paper, we describe the multiple LOSs measurement of the atomic and molecular emissions for the investigation of the location and intensity distributions in the LHD.…”