Investigation of dc generated plasmas using terahertz time domain spectroscopy

Karaoğlan, Gülten
This thesis is on the topic of investigation of the characteristics of DC Glow Discharge plasmas. Emphasis is given on characterizing the plasma electron density. The methods of generating and detecting THz pulses are described. THz transmission spectroscopy and plasma emission spectroscopy is examined. Transmission spectrum is taken for Air, gaseous Nitrogen and Argon plasmas. Moreover, emission spectrum of Air, N2 and Ar plasma analysis were done respectively. It was found that the transmission of terahertz pulses through nitrogen plasma was considerably affected compared to that of the argon plasma. Initially Drude model theory of electron conduction is employed to analyze the plasma density.


Observed nonlinearities in a DC semiconductor-gas discharge system
ÇAYLI, YAVUZ KERİM; MANSUROĞLU, DOĞAN; Uzun Kaymak, İlker Ümit (Canadian Science Publishing, 2018-07-01)
Nonlinear behaviour of a direct current (DC) driven semiconductor-gas discharge plasma is investigated experimentally. The setup consists of two planar electrodes separated by a gap of 1 mm. Plasma glow is generated between a semiconductor cathode and a transparent anode using nitrogen gas at partial atmospheric pressure. Nonlinear behavior of the discharge is investigated by varying the applied DC voltage while monitoring the plasma current (I), voltage (V), and the optical emission, (i.e., amplified volta...
Synthesis of carbon nanotubes by a plasma based pulsed electron beam generator
Goktas, H.; Ayhan, U. B.; Gündüz, Güngör; Disbudak, H.; Eryilmaz, E.; Oke, G.; Cicek, B.; Somer, M. (IOP Publishing, 2006-01-01)
Carbon nanotubes (CNTs) were synthesized by using a plasma based electron beam generator, which has a fast filamentary discharge formed from the superposition of an ordinary low-pressure dc glow and a high-current pulsed discharge. To our knowledge, CNTs are synthesized for the first time by this method. Acetylene was used as the carbon source and the iron catalyst coated silica substrates were prepared by the sol-gel technique. The silica plates were first coated with an appropriate iron (III) nitrate solu...
Study of phase transitions in polymorphic liquid crystals
Nesrullajev, A; Salihoglu, S; Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 1998-01-01)
This work presents our investigations of mezomorphic properties of two polymorphic liquid crystals, namely, 4-nonyloxy-4-butoxyphenyl benzoate and N-(-4-heptyloxybenzylidene-4-butylaniline) in a wide temperature range, particularly, in the phase transition regions. By means of an original Experimental method. the heterophase regions and also the phase transition temperatures have been determined for these materials with high accuracy. These phase transition intervals have been analyzed using a mean field mo...
Numerical investigation of a dc glow discharge in an argon gas: two-component plasma model
Kemaneci, Efe Hasan; Rafatov, İsmail; Department of Physics (2009)
This thesis deals with a one and two dimensional numerical modeling of a low-pressure DC glow discharge in argon gas. We develop two-component fluid model which uses the diffusion-drift theory for the gas discharge plasma and consists of continuity equations for electrons and ions, as well as Poisson equation for electric field. Numerical method is based on the control volume technique. Calculations are carried out in MATLAB environment. Computed results are compared with the classic theory of glow discharg...
Modelling of non-uniform DC driven glow discharge in argon gas
Rafatov, İsmail; BILIKMEN, S. (Elsevier BV, 2007-07-16)
Physical properties of non-uniform DC-driven glow discharge in argon at pressure 1 torr are analyzed numerically. Spatially two-dimensional axial-symmetric model is based on the diffusion-drift theory of gas discharge. Results presented compare favorably with the classic theory of glow discharges and exhibit good agreement with the experimental result. Comparison with the result of spatially one-dimensional model is performed. (c) 2007 Elsevier B.V. All fights reserved.
Citation Formats
G. Karaoğlan, “Investigation of dc generated plasmas using terahertz time domain spectroscopy,” M.S. - Master of Science, Middle East Technical University, 2010.