Numerical modeling and X-ray spectroscopy of ECR-plasmas

X-ray spectrometry on the plasma of electron cyclotron resonance (ECR) ion sources in connection with numerical modeling allows to determine the distr ibutions of electron energy and ion charge of the undisturbed ECR discharge . Traditionally, the ion charge state distribution is obtained by q/A analy sis of an ion beam extracted from the plasma. However, the beam expands fro m a limited plasma edge and the extraction process disturbs the plasma prop erties in this region. The beam composition does not correspond anymore to the bulk plasma composition. Furthermore, the ion transport from the plasma edge to the detection device is charge-state sensitive. This can falsify t he result additionally. In this work, the balance equations for the ion den sities and the electron energy distribution are solved numerically consider ing the main atomic processes. Using the obtained ion charge state distribu tion X-ray spectra are calculated and compared to measured ones. Modelled s pectra are fitted by adjusting input parameters of the simulation. This met hod seems to be more accurate than the traditional one. It was applied to n itrogen X-ray spectra of 14.5 GHz ECR plasma respectively to neon X-ray spe ctra of 7.5 GHz ECR plasma. (C) 2000 Elsevier Science B.V. All rights reser ved.