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To clarify the production mechanism of a large-diameter uniform electron cyclotron resonance (ECR) plasma generated by a circular TE01 mode microwave experimentally, the wave propagation characteristic in the plasma is measured with an interferometer. It is shown that a microwave introduced into the chamber is transformed mainly into an electron cyclotron wave and then entirely absorbed around the resonance point. Furthermore, it is experimentally proven that the correspondence between the radial distribution of the electric field intensity of injected microwaves and that of waves propagating in plasma may depend on the magnetic field intensity around the injection point. It is also confirmed that it is necessary to optimize the magnetic field configuration to generate a uniform ECR plasma since the absorption region of microwaves is as wide as from ω/ω c e ∼0.65 to adjacent to the resonance point.

Recently in various fields, numerous researches are going on for the assessment of material damage on the basis of crack initiation and propagation. Various methods are available in NDT for this purpose, among which analysis using released acoustic emission (AE) waves due to crack propagation is very effective due to its dynamic monitoring features. Various approaches are proposed for long time to make it an ideal method for accurate monitoring of crack behaviors in materials. In fragmentation theory there are some proportionality among the relations of AE event, AE energy, area and volume of cracks etc., which are calculated from the released AE waves from any dynamic crack. It has been found that the necessity of calculating the fractal dimension is important in verifying these relationships. This parameter is emphasized for determining the geometry of the irregularity in crack surface and crack volume. In this paper a novel approach based on image processing is proposed to find out the fractal dimension for analyzing the crack propagation characteristics. Finally, the proportionality relationships of AE parameters with crack propagation behavior in ferrite cast iron under fatigue loading are demonstrated experimentally.

An electron cyclotron resonance plasma using a circular TE01 mode microwave is generated to achieve larger diameters. It is shown that the input power of the circular TE01 mode is efficiently consumed to generate electron cyclotron resonance plasmas. The density and temperature of electrons is around 1012 cm−3 and 3–5 eV at 5 kW input power, respectively.

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