Numerical simulation of two-dimensional collisionless plasma flows under the effect of electrostatic forces via particle in cell method

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Havacılık ve Uzay Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: ÖZGÜR TÜMÜKLÜ

Danışman: MEHMET CEVDET ÇELENLİGİL

Özet:

Taking its name from its ability to generate thrust via electricity, the concept of electric propulsion has important space mission applications like station keeping for satellites and deep space probe. However, contamination of plumes in electric propulsion systems with ion beam could hinder communication, and effective neutralization is essential to clear away this predicament. Today, computer simulation is regarded as a powerful tool to investigate plasma behavior in the plumes of electric propulsion devices. The aim of this thesis is to write a generic simulation code named as SIMPFORT which studies two-dimensional, collisonless plasma flows under the effect of electrostatic forces using the Particle in Cell (PIC) method. The conservation of mass, momentum and energy are checked. In this thesis, the flows with negligible forces from magnetic fields are investigated and electrostatic Poisson’s equation is solved in both rectangular and non-rectangular domains. Successive Over Relaxation (SOR) method is implemented in the solution of the Poisson’s equation. SIMPFORT can handle plasma problems using either an accurate full kinetic particle model or an approximate hybrid model which combines kinetic and continuum (fluid) models. In the full kinetic model, both ions and electrons are simulated as particles, but in the hybrid model only ions are simulated as particles while electrons are modeled as fluid using the Boltzmann relation. In the full kinetic model the Poisson’s equation is linear, on the other hand, in the hybrid model it becomes nonlinear due to the effect of the Boltzmann relation. In this thesis, two generic test problems are solved and the results are compared with a demo version of a commercial full kinetic code named VORPAL. The present full kinetic model results compare favorably with those of VORPAL for both test problems. On the other hand, the hybrid model results show some deviations in one of the test problems.