Two-dimensional Electromagnetic Model Research Articles

Preliminary design of an impedance matching circuit for a high power rectangular RF driven ion source

Within the framework for the development of a radio frequency driven positive ion source for fusion applications, KAERI is currently constructing a new high power large area radio frequency ion source. An impedance matching circuit maximizing the power transfer to a plasma in the ion source, while taking into account the technical feasibility, is preliminarily designed at a conceptual level. In order to estimate the plasma load impedance and design parameters, an integrated model composed of the hydrogen plasma global model, the two-dimensional electromagnetic model, the relative plasma dielectric constant calculation module, and the impedance matching circuit module is developed for the ion source with a rectangular tube geometry. By employing this design model, the design parameters dependent on RF input powers of up to 50kW are investigated and the preliminary design is assessed.

Two-dimensional electromagnetic model of a microwave plasma reactor operated by an axial injection torch

This paper presents a two-dimensional electromagnetic model for a microwave (2.45 GHz) plasma reactor operated by an axial injection torch. The model solves Maxwell’s equations, adopting a harmonic time description and considering the collision dispersion features of the plasma. Perfect-conductor boundary conditions are satisfied at the reactor walls, and absorbing boundary conditions are used at the open end of the coaxial waveguide powering the system. Simulations yield the distribution of the electromagnetic fields and the average power absorbed by the system for a given spatial profile of the plasma density (tailored from previous experimental measurements), with maximum values in the range 1014−1015 cm−3. Model results reveal that the system exhibits features similar to those of an air-filled, one-end-shorted circular metal waveguide, supporting evanescent or oscillatory solutions for radial dimensions below or above a critical radius, respectively. Results also show that the fractional average power absorbed by the plasma is strongly influenced by the system dimensions, which play a major role in defining the geometry pattern of the electromagnetic field distribution. Simulations are used to provide general guidelines for device optimization.

Measurements of Reactor-Relevant Electromagnetic Effects with the FELIX Facility

In predicting the electromagnetic consequences of a plasma disruption in a tokamak reactor design, a two-dimensional electromagnetic model of the first wall, blanket, and shield (FWBS) system is typically used. The response to a decaying plasma current is then found to be dominated by a single eddy-current mode, with a single L/R time. Recent experiments with the Fusion ELectromagnetic Induction eXperiment (FELIX) facility at Argonne National Laboratory suggest that such modeling can be used to design against electromagnetic forces and torques, but only if a range of values is used for both tau, the plasma decay time, and tau/sub 0/, the L/R time of the FWBS system.