Numerical modelling of spatio-temporal patterns in a DC-driven gas discharge-semiconductor system

Özden, Gözde
In this thesis, numerical modelling of temporal and spatial pattern formation in the planar layered system, consisted of a DC driven planar gas discharge layer, coupled to high ohmic semiconductor layer, is carried out in 1D and 2D Cartesian geometry. Numerical model includes continuity equations for ions and electrons, the Poisson equation for the electric field, the energy balance equation for the background gas. The conditions correspond to a transition from the Townsend regime to the glow discharge. Calculations are performed for the nitrogen at medium pressure, using Comsol Multiphysics and Matlab packages. First, period doubling bifurcation of the system is observed within 1D model and related Lorenz maps are derived. Then, stable pattern formation is studied within 2D model. The effects of different modelling approaches, including the effect of heating of the background gas is examined.


Investigation of nonlinear oscillations in the gas discharge-semiconductor system: effect of different fluid modelling approaches
Yeşil, Cihan; Rafatov, İsmail; Department of Physics (2018)
The work deals with the study of nonlinear oscillations in a system, consisted of planar glow discharge layer, coupled to a high-ohmic semiconductor layer. The whole system is sandwiched between two planar electrodes, to which the DC voltage is applied. The discharge models are developed in Comsol Multiphysics (v5.2), and based on fluid description of plasma, with drift-diffusion approximation for charged particle fluxes. Numerical tests are carried out for the discharge in Nitrogen, with GaAs semiconductor la...
Numerical Study Of Nonlinear Oscillations And Pattern Formation İn Glow Discharge Semiconductor System
Rafatov, İsmail; Çakır, Serhat (2014-02-01)
We studied asystem consisted of a planar glow discharge layer with short length in the forward direction and wide lateral dimensions, which iscoupled to a semiconductor layer with low conductivity. The whole structure is sandwiched between two planar electrodes, to which a dc voltage is applied. Experiments show that such a system can create different homogeneous stationary and homogeneous oscillating modes, patterns with spatial and spatiotemporal structures. We develop...
Nonlinear Vibrations of a Functionally Graded Material Microbeam with Geometric Nonlinearity
Uz, Canan; Ciğeroğlu, Ender (2017-02-02)
In this paper, nonlinear vibration analysis of micro scale functionally graded material (FGM) beams with geometric nonlinearity due to large deflection is studied using modified couple stress theory (MCST). MCST is a nonlocal elasticity theory which includes a material length scale parameter since the size of an atomic microstructure becomes comparable to the length of the microbeam. Equations of motion of the micro scale FGM beam are obtained by using Hamilton's principle. Nonlinear free vibrations of the ...
Numerical Modeling of Electromagnetic Scattering from Periodic Structures by Transformation Electromagnetics
ÖZGÜN, ÖZLEM; Kuzuoğlu, Mustafa (2016-09-22)
The transformation electromagnetics is applied to the modeling of electromagnetic scattering from periodic structures in conjunction with the finite element method with periodic boundary conditions. In a unit cell of periodic structure, a uniform mesh is used over a flat surface and the arbitrary periodic surface is modeled by a coordinate transformation. The major advantage of this approach is that arbitrary geometries can be handled by using a single and simple mesh. Therefore, repeated computations (such...
Numerical Solution and Stability Analysis of Transient MHD Duct Flow
Tezer, Münevver (2018-11-01)
This paper simulates the 2D transient magnetohydrodynamic (MHD) flow in a rectangular duct in terms of the velocity of the fluid and the induced magnetic field by using the radial basis function (RBF) approximation. The inhomogeneities in the Poisson’s type MHD equations are approximated using the polynomial functions (1+r) and the particular solution is found satisfying both the equations and the boundary conditions (no-slip and insulated walls). The Euler scheme is used for advancing the solution to ste...
Citation Formats
G. Özden, “Numerical modelling of spatio-temporal patterns in a DC-driven gas discharge-semiconductor system,” M.S. - Master of Science, Middle East Technical University, 2015.