Microwave power at 14 GHz has excited a H₂ plasma in a 2 cm inner diameter 9 cm long alumina tube to generate negative hydrogen ion (H⁻) beam. A pair of permanent magnets created a magnetic field with the intensity corresponding to an electron cyclotron resonance condition for the input microwave. The ion source produced stable plasmas with the H₂ pressure more than 0.5 Pa, while the amount of H⁻ current decreased exponentially against increasing ion source pressure above 0.6 Pa. When the source produced H⁻ beam with constant H₂ pressure at 0.6 Pa, the H⁻ beam current saturated against the increase of microwave power above 200 W. These characteristics of the H⁻ beam current indicate poor transport of vibrationally excited hydrogen molecules and that of H⁻ to the ion extraction electrode.

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Analytical thrust model for the Lissajous Helicon Plasma Accelerator (LHPA) is developed by extending previous works [1, 2] in order to guide experiments for achieving feasible value of the thrust. In the LHPA, a rotating transverse electric field in an external divergent magnetic field drives azimuthal currents via electron E × B drift then the thrust is produced due to the Lorentz force. One dimensional (1D) analytical model is developed which includes the electric field penetration into the plasma and the E × B current estimation based on a trajectory analysis. Thrust as a function of parameters of the plasma density and the magnetic field is studied. The penetration of the electrical field into plasmas is examined by 1D particle in cell (PIC) simulations whose results are consistent with those of the 1D analytical model.

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A 3D scanner is a device that measures 3D objects in the real world and converts them to 3D digital data. However, much noise and several loss areas (holes) are observed in the outputted data, especially when using a low-cost 3D scanner. The purpose of this study is to propose a method for noise removal, burying holes, and outputting a smooth 3D model. We propose a smoothing method employing the multi-level partition of unity implicit (MPU) method. This method can compute a continuous surface by using implicit functions, enabling noise and loss area removal. However, the output 3D data generated by this method is not often accurate because the MPU method is sensitive to noise. Therefore, before applying the MPU method, we applied a noise reduction process. In this study, we propose a system that can grasp smooth 3D object data by using a low-cost 3D scanner.

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Electron temperature fluctuations are measured with a rotatable triple probe in PANTA. Effects of fluctuation phase are cancelled by aligning the probe pins in the propagation direction of fluctuations. Evaluated electron temperature fluctuations normalized by average electron temperature are much smaller than normalized density fluctuations and normalized floating potential fluctuations in low electron temperature PANTA plasma. Additionally conditional sampling technique is applied to a single probe measurement.

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Tomographic reconstruction for a tangentially viewing two-dimensional (2D) imaging system is studied. A method to calculate the geometry matrix in 2D tomography is introduced. An algorithm based on a Phillips-Tikhonov (P-T) type regularization method is investigated, and numerical tests using the P-T method are conducted with both tokamak and Heliotron configurations. The numerical tests show that the P-T method is not sensitive to the added noise levels and the emission profiles with higher mode numbers can be reconstructed with adequate resolution. The results indicate that this method is suitable for 2D tomographic reconstruction for a tangentially viewing vacuum ultraviolet telescope system.

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