Plasma predictions: past, present and future

• Published in: Plasma sources science & technology 2013-04, Vol.22 (2), p.23002
• Main Author: Lowke, J J
• Format: Article
• Language: English
• Subjects: ball lightning; cathode fall; electrical breakdown; solar system; welding physics
• ISSN: 0963-0252; 1361-6595
• DOI: 10.1088/0963-0252/22/2/023002

Tools for predictions of plasma properties in the last 50 years have evolved from largely analytic representations, for example using Bessel functions, to the present methods, which extensively use computers. Furthermore, there is a marked unification of predictive capabilities, spanning the use of basic atomic and molecular data such as electron-atom cross-sections, leading to the calculation of transport coefficients such as thermal and electrical conductivities and finally to detailed predictions of plasma processing, e.g. the influence of fluxes on weld profiles in arc welding. Present calculations in the range of different directions are outlined, all likely to lead to new developments in the future. The examples are (1) predictions spanning collisionless to collision-dominated plasmas-such as are required for understanding the role of cathode voltages of non-thermionic cathodes. (2) Plasma chemistry predictions-such as are required to understand electrical breakdown in air to include the role of nitrogen metastables. (3) Predictions of the interactions of ion flow and insulating surfaces-such as could explain the existence of ball lightning. Finally, (4) the greater consideration of magnetic forces on astrophysical plasmas, which may explain the regular properties of the solar system.