摘要:

AbstractIt is shown that in a two‐electron‐temperature plasma a finite amplitude upper‐hybrid wave can parametrically decay into an electrostatic electron acoustic wave (EAW) and a left handed circularly polarized (LHCP) electromagnetic wave propagating along the magnetic field. The electromagnetic oscillating two stream instability is also discussed in the same system. The role of second electron component is discussed with its application in lab plasma as well as in space p

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310402

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractCoherent wave‐wave coupling can produce radiation with a high efficiency. Recently, there has been a great deal of interest in the study of electro‐magnetic wave generation in magnetized plasmas. We have investigated theoretically the effect of finite ion temperature on the parametric instability of an electro‐static upperhybrid pump into an X‐mode nonthermal radiation and low frequency ion waves in a two electron temperature plasma. The latter may include the lower‐hybrid, the electron‐acoustic and the ion‐cyclotron waves. The loss cone distribution existing permanently at low altitudes acts as a free energy source generating the upper‐hybrid waves. The upper‐hybrid waves can also be present because of a linear instability produced by runaway electrons. Nonlinear dispersion relation and the growth rates are derived for each case using the hydrodynamical model. We find extra numerical factor arising due to the ions of finite temperature in the growth rate expression. This study may be useful in magnetosphere, auroral ionosphere, solar wind, solar radio bursts, and laboratory plasmas where ion has finite temperature and electrons have two distinct ene

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310403

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe interpretation of the author's previously given results regarding the space charge sheath model between an infinite low temperature plasma composed of electrons, single charged ions and their parent gas and the planar floating wall is extended supposing dissociative recombination instead of the less probable radiative one while the normalized numerical results remain the same.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310404

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractA hydrodynamic description of a low‐pressure discharge with singly and doubly‐charged positive ions in the high ionization regime is given. Modified hydrodynamic equations are used to include the neutral gas depletion by ionization processes under free‐flight conditions. Analytical formulas for the concentrations of the two species of ions at the discharge axis are derived.Numerical results for the radial drift velocities, the radial distributions of the densities and the neutral gas temperature are presented. The nature of the dip in the density profile of the singly‐charged ions and the decrease in their radial drift velocity near the axis with increasing degree of ionization are di

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310405

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractResults of measurements of the radial distributions of intensities of the He I and He II spectral lines emitted by the transverse and longitudinal hollow cathode discharges direct current excited are presented. The results show that both hollow cathode discharges exhibit different excitation efficiency of the spectral lines. The metastable level 2s3Sseems to be important for excitation of He I emission lines.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310406

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractPlasma ablation effect on the heat transfer from the superthermal corona to the inner cold dense core in the case ofZlayered plasma target is analysed. Thermalisation of core with the surrounding corona depends on the laser wavelength, the ‘flux‐limit’ parameter, width ofZlayer and the mean electron temperature of the overlapping region between the core and the corona. The presence ofZlayer reduces the electronic mean free path and consequently the width of the plasma ablation zone. Considering the self‐regulation condition for the heating of plasma target, the dependence of core‐corona coupling on the “flux‐limit”, the laser and plasma parameters h

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310407

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractA pulsed high‐frequency discharge was used to excite a non‐LTE (local thermal equilibrium) plasma with a high specific power density sufficiently high to dissociate oxygen and gaseous oxides. If traces of hydrocarbons were present in the gas mixture, in the spectrum the Violet system of CN appeared with a long radiation decay time. The CN bands are excited preferentially by inelastic collisions with metastable nitrogen molecules (A3σ). These levels can be efficiently depopulated by competing impact with atomic oxygen. By measuring the radiation signal during the radiation decay a dynamic range of 6 was achieved for a variation of the oxygen content between 1 and 100 ppm.The measured radiation decay of the violet CN0–0‐bands at 388 nm was simulated by a simple model of rate equations valid in the time region where diffusion processes may be n

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310408

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe correlation between the plasma resistance and the laser output parameters has been investigated in pulsed CO2— N2discharges. The strong increase of the discharge resistance during gas degradation can be explained on the basis of strong attaching gas components. In degraded mixtures a supression of discharge instabilities together with the restoration of the laser pulse energy is possible by increasing the reduced electric fieldE/Ntemporaril

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310409

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe mechanism of plasma resistance increase found in sealed CO2—N2discharges has been analyzed. From the various species occuring in such discharges only oxides of nitrogen seem to be suitable candidates. Indeed the degradation process can be simulated by adding a certain amount of N2O. The failure in detection of these contaminants in naturally degraded mixtures suggests the involvement of complex molecular species depending strongly on the discharge condition

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310410

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractEvaporation of emitter material from electrodes of fluorescent lamps has been measured by means of atomic absorption of Ba. A hollow‐cathode discharge lamp served as background radiator. The arrangement is briefly described. Spot resolved measurements has been done in preheating and in discharge regimes. Essential results are dependence on evaporation rate and filament structure, evaporation and arising of cathode spot in discharge, and diminished evaporation regarding preheatin

ISSN:0863-1042    

DOI:10.1002/ctpp.2150310411

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY