Ion distribution function in a plasma with uniform electric field

• Published in: Physics of plasmas Vol. 19; no. 11
• Main Authors: Lampe, M., Röcker, T. B., Joyce, G., Zhdanov, S. K., Ivlev, A. V., Morfill, G. E.
• Format: Journal Article
• Language: English
• Published: United States 01.11.2012
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCURACY; CHARGE EXCHANGE; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COLLISIONS; Computer simulation; COMPUTERIZED SIMULATION; CROSS SECTIONS; DIFFERENTIAL EQUATIONS; DISTRIBUTION FUNCTIONS; ELECTRIC FIELDS; ENERGY DEPENDENCE; EXACT SOLUTIONS; IONS; Mathematical models; MONTE CARLO METHOD; Monte Carlo methods; PLASMA; Plasma (physics)
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.4768456

For a homogeneous partially ionized plasma subject to a uniform electric field E, several methods and models are used to calculate the distribution function f(v) for ions subject to charge-exchange collisions. The exact solution for f(v), based on the energy-dependent cross section for Ar, is obtained by Monte Carlo (MC) simulation. This is compared to the MC results for f(v), based on either a constant cross section σ or a constant collision frequency ν. The constant-σ model is found to accurately represent f(v) for any value of E, whereas the constant-ν results are qualitatively incorrect for large fields. Under the constant-σ assumption, a simple, easily solvable ordinary differential equation is obtained which reproduces the MC results with good accuracy.