Theoretical and experimental study of the duoplasmatron ion source. Part I: Model of the duoplasmatron discharge
The duoplasmatron ion source is extensively used in many domains of experimental physics. In spite of a number of publications about this source, its elementary mechanisms are not yet well understood and no similarity rules are available. These problems have to be solved in order to improve the source properties and to provide the optimum conditions to adapt the extracted ion beam to a device for a particular application. An exhaustive study of the different plasmas of the discharge has allowed us to explain the physical processes governing the behaviour of the arc with a "dual" compression: geometrically and magnetically; they are discussed briefly. The analysis of the dynamics of the charged particles allows us to propose a one-dimensional static theory of the discharge; its basis and main results-important for the derivation of the source properties — are presented and then compared to experiment and reasonable agreement is observed. Such a model may also be adapted to the magnetized discharge used in certain other ion sources.