An error study on some linear reconstruction algorithms for electrical impedance tomography.

An error analysis on the Poisson-type linear reconstruction algorithms is performed. Three types of error are discussed and it is found that re-scaling error is dominant in most cases. It is also found that the commonly used small perturbation assumption in obtaining the Poisson's equation often fails but, due to the dominance of the re-scaling error, the reconstruction of the relative impedance distribution is still feasible by using the linear algorithms. The error analysis leads to a useful understanding of the mechanism of linear reconstruction approaches.

An integral equation approach to electrical conductance tomography.

A reconstruction procedure for electrical conductance tomography developed by solving a linear Fredholm integral equation of the first kind is discussed. The integral equation is obtained from a linearized Poisson's equations. Properties of the integral equation are discussed, and problems associated with numerical solution of the equation are treated. The reconstruction requires only one matrix multiplication and therefore can be computed in a short time. Test results of the algorithm using both simulated and measured data are presented.

Detection of lower hybrid waves within a plasma by microwave scattering.

The spatial distribution and intensity of electrostatic waves injected into a hot plasma may be inferred from the scattering of millimeter microwaves. We report measurements on the 30 degrees scattering of 8.6-mm microwaves by a 500-W, 2.45-GHz slow wave excited in a linear plasma by a phased array of two waveguides. From the magnitude of the scattered signal and auxiliary measurements with probes, we infer that a large fraction of the injected power penetrates to the center of the overdense test plasma.