Numerical Calculation on a Top-Hat Plasma Particle Analyzer Using a Boundary-Fitted Coordinate System

A boundary-fitted coordinate system is applied to numerical calculation on a top-hat plasma particle analyzer to include the effect of tiny serrations on toroidal plates. The calculation of electrostatic potential inside the analyzer showed the validity of replacement of the serrated toroidal plates to virtual flat toroidal plates, since the potential between the serrated toroidal plates was almost flat except for the area near both the serrated plates. Virtual flat toroidal plates equivalent to serrated plates were obtained from the results of an electric field between the serrated toroidal plates whose position was consistent with an ordinary empirical model. However, calculation of the trajectories of numerous protons revealed sensitivity difference between analyzers with serrated toroidal plates and flat toroidal plates. Such difference was reduced by introducing a path of protons whose boundary is identical to the envelopes of serration tips.