• 전기의세계
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• 제30권5호
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• pp.306-312
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• 1981

The Townsend discharge domain is generally observed with stable positive characteristics in N$_{2}$ gas discharge at low pressures differently in the others, which transfer immediately to glow dischage after self-sustaining discharge starts. In this paper, the presence of the stable Townsend discharge, applied voltage-discharge current characteristics and the effect of disgased electrode surface on stable townsend discharge are studied experimentaly in N$_{2}$ gas mixed with 0.05% of No in volume. As the result of this experiment, the stable Townssend discharge is observed only in pure nitrogen with the valve of pd.geq.8[torr.cm] (p=gas pressure, d=gap spacing), but not in gas mixtures. This is considered that No gas in gas mixtures disexcites effectively the metestble state of nitrogen.

• 한국진공학회지
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• 제21권3호
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• pp.130-135
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• 2012

드리프트-확산 근사식을 이용한 1차원 유체 방정식으로부터 선형적 안정성 이론을 전개하여 Tosend 방전에서 전자 확산이 불안정성에 미치는 영향을 관찰하였다. 본 연구에서 관찰된 바에 따르면 Townsend 불안정성은 전자 확산과 공간 전하에 의해 형성된 전기장의 효과가 결합되어 발생하며, 공간전하에 의한 효과가 작은 영역, 즉 방전 전류가 낮은 영역에서는 전자 확산 효과가 커질수록 불안정이 더 빨리 진행된다는 것이 발견되었다.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.26-31
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• 2016

The Townsend to glow discharge mode transition was investigated in the dielectric barrier discharge (DBD) helium plasma source which was powered by 20 kHz / $4.5 kV_{rms}$ high voltage at atmospheric pressure. The spatial profile of the electric field strength at each modes was measured by using the intensity ratio method of two helium emission lines (667.8 nm ($3^1D{\rightarrow}2^1P$) and 728.1 nm ($3^1S{\rightarrow}2^1P$)) and the Stark effect. ICCD images were analyzed with consideration for the electric field property. The Townsend discharge (TD) mode at the initial stage of breakdown has the light emission region located in the vicinity of the anode. The electric field of the light emitting region is close to the applied field in the system. Immediately, the light emitting region moves to the cathode and the discharge transits to the glow discharge (GD) mode. This mode transition can be understood with the ionization wave propagation. The electric field of the emitting region of GD near cathode is higher than that of TD near anode because of the cathode fall formation. This observation may apply to designing a DBD process system and to analysis of the process treatment results.

• 전기의세계
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• 제28권1호
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• pp.73-82
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• 1979

There are a great number of papers on the Townsend discharge in gases, and many of them are concerned with the effect of the cathode. It has been regarded that there are two kinds of effect of the electrodes, especially of the cathode; (a) the effect caused by the difference of the cathode material and (b) the effect by the change of the cathode surface state even in the same material. Both of them may change the secondary coefficient following after the change of the work function, and the atter may further change the primary ionization coefficient as foreign atoms on the surface may be dseorbed in sparks to decrease the purity of the gas. Thus the two effects must be investigated independently to study the roles of the cathode in gas discharges. In this report the effect of the cathode material on the sparking voltage is described. The experiment is also carried out under the condition that the desorption of impurities from the cathode be negligible. From these the new correlativity between the work function of the cathode and the sparking voltage is obtained. In addition, the interesting character of the minimum point of the Paschen's curve can be found.

• 대한전기학회논문지
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• 제34권7호
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• pp.289-296
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• 1985

The Townsend primary ionization coefficient a was measured by the luminous-flux method using the fact that the intensity of radiant light is proportional to electron density in the townsend discharge domain. The ranges of measurements were 15for He gas and 10

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권5호
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• pp.215-219
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• 2004

The effects of ambient temperature on the discharge characteristics of Ne-Xe based micro discharge cells for ac-PDP (plasma display panel) have been studied. In ramp voltage driving, which is generally used as a reset method of PDP, two dissimilar modes of strong and weak discharge were found. As the interval between the former sustaining discharge and ramp voltage discharge becomes greater, the probability of a strong discharge increases. This suggests that a sufficient number of priming particles is necessary for initiating weak mode (Townsend discharge). It was discovered that under higher ambient temperatures, weak discharge occurs more frequently. The discharge time lag observed in square pulse driving of single cells becomes surprisingly smaller under higher ambient temperatures for the constant gas number density condition.

• E2M - 전기 전자와 첨단 소재
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• 제10권4호
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• pp.342-348
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• 1997

In this paper, the behavior of electron swarm parameters and energy distribution function of the discharge under high E/N condition in e$^{-10}$ -CF$_{4}$ gas have been analysed over the E/N range from 1-300(Td) by the MCS and BEq methods using set of electron collision cross section determined by the authors. The swarm parameters and energy distribution function have been calculated for the pulsed Townsend, steady-state Townsend and Time of Flight methods. The results gained that the value of electron swarm parameters such as the electron drift velocity, the electron ionization and attachment coefficients and longitudinal diffusion coefficients in agreement with the experimental and theoretical data for a range of E/N. The electron energy distribution function has been explained and analysed in e$^{-10}$ -CF$_{4}$ at E/N : 5, 10, 100, 200, 300(Td) for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The validity of the results has been confirmed by TOF and SST methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.224-225
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• 2007

This paper is to be linked the discharge theory with parameter t the coefficient of restitution used in physics. The collisions is of particular importance in high voltage engineering, nuclear, and high-energy physics. Here the bodies collided may be atoms, nuclei or various elementary particles, such as electrons, protons, and so on.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.753-755
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• 1988

In this paper, the effective ionization coefficients (${\alpha}-{\eta}$/Po) are measured by the steady state Townsend method in Townsend discharge domain. The effective ionization coefficients are measured in the range 75${\leqq}$E/Po${\leqq}$150(V/Torr. cm) in $SF_{6}$. The values of the effective ionization coefficients are easily and precisely determined by means of the linearization of current growth equation. The effective ionization coefficients of $SF_{6}$ were agreement with that of Bhalla and Craggs.

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.571-580
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• 1998

The numerical model that can describe the ignition of pseudospark discharge using hybrid fluid-particle(Monte Carlo )method has been developed. This model consists of the fluid expression for transport of electrons and ions and Poisson's equation in the electric field. The fluid equation determines the spatiotemporal dependence of charged particle densities and the ionization source term is computed using the Monte carlo method. This model has been used to study the evolution of a discharge in Argon at 0.5 torr, with an applied voltage if 1kV. The evolution process of the discharge has been divided into four phases along the potential distribution : (1) Townsend discharge, (2) plasma formation, (3) onset of hollow cathode effect, (4) plasma expansion. From the numerical results, the physical mechanisms that lead to the rapid rise in current associated with the onset of pseudospark could be identified.