Measurement of thickness of film deposited on the plasma-facing wall in the QUEST tokamak by colorimetry.

After several experimental campaigns in the Kyushu University Experiment with Steady-state Spherical Tokamak (QUEST), the originally stainless steel plasma-facing wall (PFW) becomes completely covered with a deposited film composed of mixture materials, such as iron, chromium, carbon, and tungsten. In this work, an innovative colorimetry-based method was developed to measure the thickness of the deposited film on the actual QUEST wall. Because the optical constants of the deposited film on the PFW were position-dependent and the extinction coefficient k was about 1.

Unique XCI evolution in Tokudaia: initial XCI of the neo-X chromosome in Tokudaia muenninki and function loss of XIST in Tokudaia osimensis.

X chromosome inactivation (XCI) is an essential mechanism to compensate gene dosage in mammals. Here, we show that XCI has evolved differently in two species of the genus Tokudaia. The Amami spiny rat, Tokudaia osimensis, has a single X chromosome in males and females (XO/XO).

Development of a tunable Fabry-Perot etalon-based near-infrared interference spectrometer for measurement of the HeI 2³S-2³P spectral line shape in magnetically confined torus plasmas.

In magnetically confined torus plasmas, the local emission intensity, temperature, and flow velocity of atoms in the inboard and outboard scrape-off layers can be separately measured by a passive emission spectroscopy assisted by observation of the Zeeman splitting in their spectral line shape. To utilize this technique, a near-infrared interference spectrometer optimized for the observation of the helium 2(3)S-2(3)P transition spectral line (wavelength 1083 nm) has been developed. The applicability of the technique to actual torus devices is elucidated by calculating the spectral line shapes expected to be observed in LHD and QUEST (Q-shu University Experiment with Steady State Spherical Tokamak).

Dynamical programming based turbulence velocimetry for fast visible imaging of tokamak plasma.

An orthogonal dynamic programming (ODP) based particle image velocimetry (PIV) technique is developed to measure the time resolved flow field of the fluctuating structures at the plasma edge and scrape off layer (SOL) of tokamaks. This non-intrusive technique can provide two dimensional velocity fields at high spatial and temporal resolution from a fast framing image sequence and hence can provide better insights into plasma flow as compared to conventional probe measurements. Applicability of the technique is tested with simulated image pairs.

Thermal imaging of plasma with a phased array antenna in QUEST.

A thermal imaging system to measure plasma Electron Bernstein Emission (EBE) emanating from the mode conversion region in overdense plasma is discussed. Unlike conventional ECE/EBE imaging, this diagnostics does not employ any active mechanical scanning mirrors or focusing optics to scan for the emission cones in plasma. Instead, a standard 3 × 3 waveguide array antenna is used as a passive receiver to collect emission from plasma and imaging reconstruction is done by accurate measurements of phase and intensity of these signals by heterodyne detection technique.