Radial Electric Fields from Larmor Radius Effects in the Field-Reversed theta Pinch

摘要

The generation of radial electric field from the different Larmor radii between the diffusing ions and electrons in Field-Reversed Theta Pinch (FR theta P) has been evaluated by developing a new computer code, FLR. The code treats the background electrons at point particles, while for large-orbit ions the effects of finite Larmor radius are incorporated into an accurate density formulation. This is necessary since in a small device whose size is comparable to an ion gyroradius (e.g., FR theta P) most ions will contribute to the density over a fairly large region of the plasma. The actual ion density at any point in the plasma represents a time-averaged contribution from all particles whose gyro-orbits pass through that point. The FLR code has predicted the electric field strengths between 10 exp 3 and 10 exp 4 volts/cm, which is in good agreement with the experimental values of FRX-A measurements which correspond roughly to the order of 10 exp 3 volts/cm. (ERA citation 05:039148)