Наукові роботи. Навчально-науковий інститут "Фізико-технічний факультет"

Постійне посилання колекціїhttps://ekhnuir.karazin.ua/handle/123456789/1172

Переглянути

Зараз показуємо 1 - 20 з 267

Low-pressure gas breakdown in combined fields
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 1994-11) Lisovskiy, V.; Yegorenkov, V.
This paper reviews measured and theoretical data relating to the low-pressure discharge breakdown in DC and uniform RF fields and their combination. The original results on determination of molecular constants of various gases from breakdown curves obtained by the authors are given. We have investigated the effect of the DC electric field on the RF breakdown pattern. In particular the influence of the DC electric field on the ambiguity region of the RF discharge breakdown curves has been determined. Breakdown equations in combined fields have been derived and comparison has been made between these equations and measured data. Simple analytical criteria for gas breakdown for a wide range of parameters have been given.
Влияние вторичной электронной эмиссии на ВЧ пробой газа низкого давления
(Письма в Журнал Технической Физики, 1996-11) Лисовский, В.; Кропотов, Н.; Фареник, В.
Влияние вторичной электронной эмиссии на ВЧ пробой газа низкого давления
Определение коэффициентов переноса электронов в аргоне из кривых зажигания ВЧ и комбинированного разрядов низкого давления
(Письма в Журнал Технической Физики, 1998-04) Лисовский, В.
Из кривых зажигания высокочастотного (ВЧ) и комбинированного (ВЧ + постоянное электрическое поле) разрядов низкого давления определены значения дрейфовой скорости электронов Vdr в диапазоне E/p~70-2000 V/(cm·Torr) и отношение коэффициента продольной диффузии к подвижности электронов DL/mue в диапазоне E/p~1-2000 V/(cm·Torr).
Особенности alpha-gamma-перехода в ВЧ разряде низкого давления в аргоне
(Журнал Технической Физики, 1998-05) Лисовский, В.
Получено, что область устойчивого существования alpha-режима высокочастотного (ВЧ) разряда ограничена не только со стороны средних давлений, но и со стороны низких давлений. Особенностью alpha-gamma-перехода ВЧ разряда низкого давления является то, что критерий пробоя приэлектродного слоя не выполняется. Показано, что при низких давлениях alpha-gamma-переход ВЧ разряда в аргоне происходит скачком и имеет гистерезисный характер. При промежуточных давлениях alpha-gamma-переход происходит непрерывно, без скачков, при этом появляется отрицательная дифференциальная проводимость, формируются двойные слои, в центре разряда наблюдается немонотонное поведение плотности плазмы. Обсуждается роль стохастического (бесстолкновительного) нагрева электронов в поддержании ВЧ разряда при промежуточных давлениях газа.
Rf breakdown of low-pressure gas and a novel method for determination of electron-drift velocities in gases
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 1998-12) Lisovskiy, V.; Yegorenkov, V.
This paper reports the results of the detailed and comprehensive experimental and theoretical treatment of the rf gas breakdown. We give the measured breakdown curves of the low-pressure rf discharge in argon, hydrogen and air in a broad range of gas pressures and interelectrode distances. The different processes of generation and loss of charged particles participating in the rf gas breakdown are discussed. We suggest to distinguish the following sections on the rf discharge breakdown curves: multi-pactor, Paschen, diffusion-drift and emission-free ones. The analytic gas breakdown criterion of the combined (rf plus weak dc electric field) discharge taking into account the anisotropy of electron diffusion in the electric field is obtained. A novel method for determining the electron-drift velocity from the measured rf breakdown curves is suggested. The electron-drift velocity data in argon, hydrogen and air obtained with this technique in the range E/p = 50–2000 V cm−1 Torr−1 are given and compared with those got by conventional means.
Electron-drift velocity determination in CF4 and SF6 in a strong electric field from breakdown curves of low-pressure RF discharge
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 1999-10) Lisovskiy, V.; Yegorenkov, V.
In this paper we report the values of the electron-drift velocity in CF4 and SF6 within the range E/p = 200–1000 V cm−1 Torr−1. We have used the recorded coordinates of the turning point on the breakdown curves of the rf capacitive discharge. We have also formulated the main requirements to the experimental device for correct recording of the breakdown curves of the low-pressure rf capacitive discharge. Our data are in good agreement with those of other authors who have used different approaches. We have also obtained the results on the electron-drift-velocity values within the E=p region where no other techniques are applicable. Our findings are also supported by numerical simulation data obtained with the application of a conventional Bolsig code.
Критерий пробоя газа в СВЧ поле
(Журнал Технической Физики, 1999-11) Лисовский, В.
Аналитически получен критерий пробоя газа в сверхвысокочастотном поле, который учитывает различие коэффициентов диффузии электронов вдоль и поперек направления электрического поля. Рассмотрены случаи зажигания разряда при отсутствии прилипания электронов к молекулам газа и в электроотрицательном газе, а также случай зажигания СВЧ разряда с наложенным слабым постоянным электрическим полем.
Scaling Law for a Low-Pressure Gas Breakdown in a Homogeneous DC Electric Field
(Journal of Experimental and Theoretical Physics Letters, 2000-02) Lisovskiy, V.; Yakovin, S.
Gas breakdown in nitrogen, air, and oxygen in a dc electric field at various interelectrode distances L is studied experimentally. A scaling law for a low-pressure gas breakdown Udc=f(pL,L/R) is deduced. According to this scaling law, the breakdown voltage Udc is a function not only of the product of the gas pressure p and the gap length L, but also of the ratio of the gap length L to the chamber radius R. It is shown that, for any dimensions of the cylindrical discharge chamber (in the range of L/R under investigation), the ratio of the breakdown electric field to the gas pressure p at the minimum of the ignition curve remains constant: (Edc/p)min = const. A method for calculating the ignition curve in a cylindrical discharge chamber with arbitrary values of L and R is proposed.
Модифицированный закон Пашена для зажигания тлеющего разряда в инертных газах
(Журнал Технической Физики, 2000-06) Лисовский, В.; Яковин, С.
Экспериментально и теоретически исследован пробой инертных газов в однородном постоянном электрическом поле при различных расстояниях между электродами L и радиусах разрядных трубок R. Показано, что при любых геометрических размерах разрядной камеры и материалах катода в минимуме кривых зажигания отношение напряженности пробойного электрического поля к давлению газа сохраняется постоянным. Получен модифицированный закон Пашена, согласно которому пробойное напряжение является функцией не только произведения давления газа на величину расстояния L, но и функцией отношения L/R.
Характеристики катодного слоя тлеющего разряда низкого давления в аргоне и азоте
(Письма в Журнал Технической Физики, 2000-10) Лисовский, В.; Яковин, С.
Экспериментально определены характеристики катодного слоя тлеющего разряда в аргоне и азоте в широком диапазоне давлений газа. Получено, что нормальный режим горения может наблюдаться только при наличии ионизации в анодном слое (справа от точки перегиба кривой зажигания тлеющего разряда). Показана некорректность одного способа определения нормального катодного падения напряжения.
Low-pressure gas breakdown in uniform dc electric field
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 2000-11) Lisovskiy, V.; Yakovin, S.; Yegorenkov, V.
This paper studies in experiment and theory the breakdown of argon, nitrogen, air and oxygen in a uniform dc electric field at different discharge gaps L, discharge tube radii R and cathode materials. At arbitrary geometric dimensions of the cylindrical discharge vessel and cathode materials the ratio of the breakdown electric field value to the gas pressure p at the minimum of the breakdown curves is shown to remain constant, (Edc/p)min ≈ constant. A modified breakdown law for the low-pressure dc discharge Udc = f (pL, L/R) is obtained. That is, the breakdown voltage Udc is shown to depend not only on the product pL, but also on the ratio L/R. A method is presented enabling one to predict a dc breakdown curve in the cylindrical discharge vessel possessing arbitrary L and R values from the measured data on the dc breakdown.
Experimental Study of a Low-Pressure Glow Discharge in Air in Large-Diameter Discharge Tubes: I. Conditions for the Normal Regime of a Glow Discharge
(Plasma Physics Reports, 2000-12) Lisovskiy, V.; Yakovin, S.
The initiation and characteristics of a low-pressure glow discharge in air in large-diameter discharge tubes are studied. A deviation from the Paschen law is observed: the breakdown curves Udc(pL) shift toward the higher values of Udc and pL as the interelectrode distance L increases. It is shown that the normal regime of a glow discharge is accompanied by gas ionization in the anode sheath. This takes place only for pL values lying to the right of the inflection point in the breakdown curve. The cathode-sheath characteristics in the normal and abnormal regimes of an air discharge for a duralumin cathode are determined. The axial profiles of the ion density, electron temperature, and plasma potential, as well as the anode voltage drop, are measured at various air pressures.
Alpha–gamma transition in RF capacitive discharge in low-pressure oxygen
(www.elsevier.com/locate/vacuum, 2004-01) Lisovskiy, V.; Yegorenkov, V.
We report the recorded current–voltage characteristics of a RF capacitive discharge in oxygen. Low-frequency oscillations of the plasma potential in a kilohertz frequency range are observed to accompany the transition of the discharge from a weak- (a-) to a strong-current (g-) regime in the low-pressure range. The weak-current regime of the RF capacitive discharge is observed within the pressure range limited not only from the medium pressure side but also from the lower-pressure one. Electron temperature and plasma density are registered with a probe technique.
Electron drift velocity in NH3 in strong electric fields determined from rf breakdown curves
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 2005-03) Lisovskiy, Valeriy; Martins, Sofia; Landry, Karine; Douai, David; Booth, Jean-Paul; Cassagne, Valerick
We report measurements of the breakdown curves of a radio-frequency capacitive discharge in low pressure ammonia. The electron drift velocity was determined from the location of turning points in the breakdown curves in the range of E/p = 42–713 Vcm−1 Torr−1. We compare our results to values calculated from the published cross-sections in the range E/p = 1–5000 Vcm−1 Torr−1 and find good agreement.
Extinction of RF capacitive low-pressure discharges
(EUROPHYSICS LETTERS, 2005-08) Lisovskiy, Valeriy; Booth, Jean-Paul; Martins, Sofia; Landry, Karine; Douai, David; Cassagne, Valerick
Breakdown and extinction curves have been measured for RF capacitive low-pressure discharges in nitrogen and hydrogen at a frequency of 13.56 MHz and discharge gaps between 6 and 25 mm. In particular, the low-pressure, high-voltage region of the extinction curves is reported for the first time. The shape of the extinction curves was found to be similar to that of the breakdown curves. At sufficiently large gaps (L > 10 mm) the RF extinction voltage was found to be multi-valued in the low-pressure region, as is observed for the breakdown voltage. In this region, extinction can occur when the voltage is increased because the width of the two sheaths occupies the whole discharge space.
The effect of discharge chamber geometry on the ignition of low-pressure rf capacitive discharges
(PHYSICS OF PLASMAS, 2005-09) Lisovskiy, V.; Martins, S.; Landry, K.; Douai, D.; Booth, Jean-Paul; Cassagne, V.; Yegorenkov, V.
This paper reports measured and calculated breakdown curves in several gases of rf capacitive discharges excited at 13.56 MHz in chambers of three different geometries: parallel plates surrounded by a dielectric cylinder (“symmetric parallel plate”), parallel plates surrounded by a grounded metallic cylinder (“asymmetric parallel plate”), and parallel plates inside a much larger grounded metallic chamber (“large chamber”). The breakdown curves for the symmetric chamber have a multivalued section at low pressure. For the asymmetric chamber the breakdown curves are shifted to lower pressures and rf voltages, but the multivalued feature is still present. At higher pressures the breakdown voltages are much lower than for the symmetric geometry. For the large chamber geometry the multivalued behavior is not observed. The breakdown curves were also calculated using a numerical model based on fluid equations, giving results that are in satisfactory agreement with the measurements.
Electron drift velocity in argon, nitrogen, hydrogen, oxygen and ammonia in strong electric fields determined from rf breakdown curves
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 2006-02) Lisovskiy, V.; Booth, Jean-Paul; Landry, K.; Douai, D.; Cassagne, V.; Yegorenkov, V.
We report measurements of the breakdown curves for low-pressure rf capacitive discharges in nitrogen, hydrogen, argon, oxygen and ammonia. The electron drift velocity in these gases was deduced, as a function of reduced electric field, from the low-pressure turning points of the breakdown curves. The equation for rf breakdown proposed by Kihara (1952 Rev. Mod. Phys. 24 52) allows the position of both the turning point and the breakdown curve minimum to be calculated from the transport properties of each gas. Therefore we propose a new technique to determine the electron drift velocity from the position of the rf breakdown curve minima. We have determined the drift velocity in the range E/p = 52–1324 Vcm−1 Torr−1 for nitrogen, E/p = 33–720 Vcm−1 Torr−1 for argon, E/p = 32–713 Vcm−1 Torr−1 for ammonia, E/p = 32–550 Vcm−1 Torr−1 for hydrogen and E/p = 69–1673 Vcm−1 Torr−1 for oxygen.
Double layer onset inside the near-electrode sheath of a RF capacitive discharge in oxygen
(www.elsevier.com/locate/vacuum, 2006-04) Lisovskiy, V.; Yegorenkov, V.
This paper reports the axial profiles of the electron temperature Te in the RF capacitive discharge in oxygen recorded with a probe technique. We observed the Te peaks near the boundaries of the sheaths as well as inside the near-electrode sheath. The Te peak inside the sheath is, probably, due to the formation of the double layer at the anode phase of this near-electrode sheath. The assumption of a double layer formation is also supported by the photos of the sheath glow making evident the bright region inside the sheath. The results of our measurements agree with our fluid simulation satisfactorily.
Electron drift velocity in N2O in strong electric fields determined from rf breakdown curves
(JOURNAL OF PHYSICS D: APPLIED PHYSICS, 2006-04) Lisovskiy, V.; Booth, Jean-Paul; Landry, K.; Douai, D.; Cassagne, V.; Yegorenkov, V.
We report measurements of the breakdown curves of an rf capacitive discharge in low pressure nitrous oxide. The electron drift velocity was determined from the locations of the turning point and of the minimum in the breakdown curves in the range E/p = 87–840 Vcm−1 Torr−1. We compare our results with values calculated from the published cross-sections in the range E/p = 1–5000 Vcm−1 Torr−1 and find good agreement.
Modes and the alpha-gamma transition in rf capacitive discharges in N2O at different rf frequencies
(PHYSICS OF PLASMAS, 2006-10) Lisovskiy, V.; Booth, Jean-Paul; Landry, K.; Douai, D.; Cassagne, V.; Yegorenkov, V.
This paper reports current-voltage characteristics and pressure-voltage transition curves from the weak-current a-mode to the strong-current g-mode for rf capacitive discharges in N2O at frequencies of 2 MHz, 13.56 MHz, and 27.12 MHz. At 2 MHz the rf discharge is mostly resistive whereas at 13.56 MHz and 27.12 MHz it is mostly capacitive. The weak-current a-mode was found to exist only above a certain minimum gas pressure for all frequencies studied [N. Yatsenko Sov. Phys. Tech. Phys. 26, 678 (19810] previously proposed that the a−g transition corresponds to breakdown of the sheaths. However, we show that this is the case only for sufficiently high gas pressures. At lower pressure there is a smooth transition from the weak-current a-mode to a strong-current g-mode, in which the sheaths produce fast electrons but the sheath has not undergone breakdown.