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- Computing DC discharges in a wide range of currents with COMSOL MultiPhysics: time-dependent solvers vs. stationary solversPublication . Almeida, P. G. C.; Benilov, M. S.; Bieniek, M. S.; Cunha, M. D.; Gomes, J. G. L.; Kaufmann, H. T. CostaThe benefits of the usage of stationary over time-dependent solvers of COMSOL Multiphysics in the modelling of DC discharges are explored and demonstrated using as examples glow and high pressure arc discharges; in particular, it is investigated whether time-dependent solvers can be used for a systematic computation of different modes of these discharges. It has been found that most modes of both glow and high-pressure arc discharges cannot be computed in the whole range of their existence by a time-dependent solver. Further, time-dependent solvers are unsuitable for a computation of all the states belonging to the retrograde sections of the current-voltage characteristics of the modes, so the discharge manifests hysteresis, which, in principle, can be observed in the experiment.
- Quenching thermal instability in the body of a thermionic arc cathodePublication . Almeida, P. G. C.; Benilov, M. S.; Cunha, M. D.; Gomes, J. G. L.The possibility of quenching the instability causing the appearance of spots on thermionic cathodes of high-pressure arc discharges is demonstrated by means of numerical simulations and experimentally. This possibility stems from the fact that the instability is of a thermal nature and therefore slow. While of significant interest by itself, this possibility may be exploited to prevent in real time the formation of cathode spots in arc devices.