2D extension of gem (the generalized ecr ion source modeling code)
To model electron cyclotron resonance (ECR) ion sources, GEM [1] is being extended to two dimensions (2D) by adding a radial dimension. The electron distribution function (EDF) is calculated on each magnetic flux surface using a bounce-averaged Fokker-Planck code with a 2D ECR heating (ECRH) model. The ion fluid model is also being extended to 2D by adding collisional radial transport terms. All species in ECRIS are balanced by assuming quasi-neutrality in each cell and the plasma potential is calculated by maintaining the ambipolarity globally. The graphical user interface (GUI) and parallel computing ability of GEM make it an easy- to-use tool for ECRIS research. Numerical results and comparisons with experimental data are presented here.
FPPAC94: A two-dimensional multispecies nonlinear Fokker-Planck package for UNIX systems☆
Abstract FPPAC94 solves the complete nonlinear multispecies Fokker-Planck collison operator for a plasma in two-dimensional velocity space. The operator is expressed in terms of spherical coordinates (speed and pitch angle) under the assumption of azimuthal symmetry. Provision is made for additional physics contributions (e.g. rf heating, electric field acceleration). The charged species, referred to as general species, are assumed to be in the presence of an arbitrary number of fixed Maxwellian species. The electrons may be treated either as one of these Maxwellian species or as a general species. Coulomb interactions among all charged species are considered This program is a new version of FPPAC. FPPAC was last published in Computer Physics Communications in 1988. This new version is identical in scope to the previous version. However, it is written in standard Fortran 77 and is able to execute on a variety of Unix systems. The code has been tested on the Cray-C90, HP-755 and Sun Sparc-1. The answers agree on all platforms where the code has been tested. The test problems are the same as those provided in 1988. This version also corrects a bug in the 1988 version.
AN EMITTANCE-MASS SCANNER FOR SMALL-MASS, LOW-ENERGY BEAMS
An on‐line emittance–mass scanner (EMS), with a size of 10 cm×10 cm×8 cm, has been developed for use with low energy and light ion beams (A<40) at TRIUMF. Computerized data acquisition and procession give the rms emittances, intensities, and contour plots of each beam component. The angular resolution of the scanner is ±1.0 mrad, the maximum divergence of each component that the scanner can take is 140 mrad. Some experimental results of the measurement are given. The comparison between the contour shapes and the values of the emittance measured by both the emittance scanner and EMS is in good agreement.