研究目的
Understanding the principle ion sinks and sources of neutral fueling is essential to understanding the ability of helicon wave heating to create high density plasmas.
研究成果
The ?ow measurements for neutral and singly ionized argon in both the axial and radial direction begin to paint a picture of the particle balance in the MARIA helicon device. The ?ux of ions ?owing along the axis of MARIA exhibits clear scaling with magnetic ?eld strength and the greatest ion loss term was due to axial ?ux near the boundary plate. The radial ion ?ux is comparable to the axial ?ux in the same region. The ion loss due to axial ?ow is therefore dominant near the axial boundaries, but radial and axial ion loss is of similar magnitude throughout the bulk plasma.
研究不足
The radial neutral LIF intensity cannot be converted into a neutral ?ux due to refraction through the glass chamber wall and signi?cantly reduced ion LIF intensity, meaning LIF measurements could not be taken right next to the chamber wall.
1:Experimental Design and Method Selection:
Laser induced fluorescence (LIF) was used to measure spatially resolved ion and neutral atom ?uxes in the MARIA helicon device at several axial and radial locations.
2:Sample Selection and Data Sources:
The measurements were taken on the MARIA helicon device, which is
3:4 m long with an inner chamber diameter of 14 cm. List of Experimental Equipment and Materials:
The LIF system follows the master oscillator power ampli?er (MOPA) design, designed around a 40 mW tunable single mode diode laser and a tapered ampli?er.
4:Experimental Procedures and Operational Workflow:
The LIF system can be tuned to pump the 3D 4F 7/2 to 4p 4D 5/2 singly ionized argon absorption transition at
5:614 nm, or the 4s 2?3/2(cid:
64) 1 to 4p 2?1/2(cid:4) 0 neutral argon absorption transition at
6:912 nm. Data Analysis Methods:
6 The LIF intensity was converted to electron density using calibration data, and the divergence of the ?ux was calculated to estimate the ionization source strength and distribution.
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