摘要:

AbstractA coupled pair of nonlinear equations for the amplitude modulated Langmuir wave and the associated low frequency electric potential wave have been derived by relaxing quasineutrality condition of the frequency motion. Solitary wave solutions exist. It is found that the small correction term due to ion pressure changes the amplitude of the solitary wave.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290202

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractTo describe the long time asymptotic behaviour of weakly nonlinear plasma waves propagating in a strongly magnetized plasmafilled cylindrical waveguide the usual KDV equation which is first order in wave amplitude is extended to second order including the effects of finite temperature, mobile ions and giving a proper treatment to the radial co‐ordinate for all possible modes of propagation. The second‐order effects on the first‐order solitary wave profile, phase speed and first order correction to the wavelength are all determined and disc

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290203

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effects of suspended particles and the finite thermal and electrical conductivities on the magnetogravitational instability of an ionized rotating plasma through a porous medium have been investigated, under varying assumptions of the rotational axis and the modes of propagation. In all the cases it is observed that the Jeans' criterion determines the condition of instability with some modifications due to various parameters. The effects of rotation, the medium porosity, and the mass concentration of the suspended particles on instability condition have been removed by (1) magnetic field for longitudinal mode of propagation with perpendicular rotational axis, and (2) viscosity for transverse propagation with rotational axis parallel to the magnetic field. The mass concentration reduces the effects of rotation. Thermal conductivity replaces the adiabatic velocity of sound by the isothermal one, whereas the effect of the finite electrical conductivity is to delink the alignment between the magnetic field and the plasma. Porosity reduces the effects of both the magnetic field and the rotation, on Jeans' criterion.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290204

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractSpontaneously excited instabilities in a uniform, collisionless and non‐magnetized active plasma are studied, under the assumption that the polarisability of its active constituent is due to transitions of only one optical electron between two inversely populated energy levels. The attention is focused on non‐resonant situations in which the modal frequencies of the excited waves differ significantly from the frequency of coherent electromagnetic radiation arising due to the presence of the active constituent. The longitudinal (‘acoustic’) waves in both low and high phase velocity domains, as well as the transverse (‘optical’) waves, are investigated. It is shown that the instabilities excited are most frequently aperiodical, and appear within, a comparatively large wavelength range. Their amplitude increments are evaluated. Under certain particular conditions, specified in the paper, the instabilities turn out to be periodical and to appear in very narrow wavelength bands only. Their modal frequencies and amplitude increments are als

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290205

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThermodynamic functions, energy level shifts, ionization equilibria and ionization kinetics for plasmas containing ions with higher charges are investigated. It is shown that multiply charged ions lead to an essential amplification of nonideality effects.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290206

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe temperature of the laser sustained plasma has been determined from the continuum emission coefficient at different wavelengths. The experiments were performed in an argon plasma at the pressure of 10 atm. The spurious continuum resulting from merging of spectral lines was investigated numerically. Its influence on the measured emission coefficient in the red region has been found to be considerable.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290207

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe reduction of the tube radius is an effective technique for enhancing power concentration. The increased wall losses are compensated by larger field strengths, which counteract the decrease in radiation efficiency with rising current density. The causal relationships are investigated for tube radii of 18‐4 mm at constant discharge currenti= 200 mA and constant current densityj= 1.2 mA/mm2and for parameter variation of the field strength only. The measured efficiencies of the Hg‐resonance lines 254 and 185 nm and the electron energy distribution functions agree well with the calculated values. Moreover, the results of the model calculations provide information on the elementary processes involved, such as elastic losses, collisions of second kind, stepwise processes and Coulomb interaction. The results show that Hg‐rare gas discharge with tube radiiR= 5–10 mm are no less suitable for light production than those with radii between 13 an

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290208

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractA model is presented of the positive column of a dc glow discharge in argon with small admixtures of hexamethyldisiloxane (HMDS). The axial electric field, the ion production rates for direct‐, stepwise‐, pair‐, and Penning ionization, the densities of metastable Ar atoms and of electrons, and the wall current of HMDS ions are calculated in dependence on HMDS admixture and discharge current density. For the calculations particle balance equations were used for a diffusion determined plasma in a mixture of two gaseous components. The reaction rates for the electron collision processes were determined applying the electron distribution function calculated for pure argon. Taking into account PENNING ionization of HMDS molecules by metastable argon atoms the decrease of electric field for increasing HMDS admixtures is according to the experimen‐tally measured values. Also ion wall currents and electron densities are compared with experimen‐tal values for thin film formation rate and results of probe mea

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290209

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe analytic solutions of the weak ion acoustic double layers in warm unmagnetized and magnetized plasma have been presented with the fluid equation for ions and an arbitrary equation of state for the hot electrons. It has been shown that double layers solutions exist for both magnetized and unmagnetized plasmas when two Boltzmann model for electrons are considered. The potential, the thickness and the velocity of such type of double layers have been calculated and compared with those for the cold plasma.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290210

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0863-1042    

DOI:10.1002/ctpp.2150290211

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY