摘要:

AbstractA review is given first on Lichtenberg figures on dielectrics in gases. The problem of Lichtenberg figures at low gas pressures (p<1 Pa) is raised. Experiments are reported about the latter. The results are discussed by the help of models of vacuum flashover on dielectrics.

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250402

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractGIS for operation voltages ≧ 245 kV can be tested with oscillating impulse voltages on site advantageously, because this H. V. test can be performed with easily mountable impulse generators. The IEC recommendation for on‐site testing of GIS which is now under discussion doesn't fix the time parameters of the oscillating impulse voltages, but these influence the breakdown behaviour of slightly non‐uniform fields with disturbances (sharpe edges, fixed or free‐moving particles) in SF2.For the mentioned GIS (≧ 245 kV) fixed disturbances are more dangerous than free‐moving particles. Therefore the breakdown voltages of model insulations with a disturbance at the H.V. electrode (needle with lengthl=0…5 mm) in SF6(p20=0.1…0.4 MPa) were investigated at oscillating lightning (OLI) and oscillating switching (OSI) impulse voltages with different times to crest.From the results, which were compared with those at aperiodic lightning (LI) or switching (SI) impulse voltages, permissible time parameters for OLI and OSI can be derived. On the basis of these parameters an impulse generator was designed which enables on‐site testing for a wide range of the capacity

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250403

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractThe reaction of a chemical active non‐equilibrium plasma system is studied within simple kinetic models in principle.Of special interest are steady states of the system with the meaning of a reversible chemical equilibrium.Starting from a schematized description of the non‐isothermal plasma chemical reactor the basic relations of the so‐called macroscopic kinetics are developed and in the case of a comprehensive example (synthesis and decomposition of ozone) compared with the corresponding microscopic kin

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250404

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractApplying the new technique for finding the converged solution of the Boltzmann equation in a weakly ionized plasma, which was developed in the first part of this paper, a comprehensive study of the electron velocity distribution function for a model plasma with elastic and exciting collisions is performed by solving the Boltzmann equation with increasing order of approximation. The purpose of this investigation is that of calculating the isotropic distributionf0, the first contributionf1to the anisotropy of the velocity distribution, the important macroscopic quantities and, more generally, that of studying the total anisotropy as well as the changes of all these quantities when the approximation degree is enlarged beyond the 2 terms of the conventional Lorentz approximation. By varying some parameters of the model plasma, that is the electric field strength, the magnitude of the excitation cross section and the excitation threshold, the main features of plasmas in inert as well as molecular gases are modelled and the impact of these parameters on the mentioned quantities is analysed. Some of the converged results are compared with results of corresponding Monte Carlo simulations.The approximation degree required to find the converged values of isotropic distribution, main macroscopic quantities and electron distribution in the velocity space (and thus its real anisotropy) is estimated by solving the Boltzmann equation over wide parameter ranges.

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250405

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractFor a hydrogen model the exchange‐correlation energy is calculated at any degree of degeneracy. The numerical data run into theT=O — RPA values, which were evaluated independently.An equation of state for hydrogen without bound states is compared with HNC‐calculations in the nondegenerate limit. The influence of increasingy=miw/me— values for the agreement with limiting results derived analytically is given in

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250406

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractIt is tried to present the main features of quark‐gluon plasma physics to a possible reader not so familiar with quantum chromodynamics and its extension to high temperatures, merely by looking for some analogies to usual electrodynamic plasma phenomena: The electrons correspond to the quarks, the photons to the gluons, the electromagnetic coupling to the strong coupling. However, in contrast to the ionization processes or, more general, generation processes of electrically charged particles or holes, the change from the usual hadronized state of nuclear matter to the collective quark‐gluon plasma state is a first‐order phase transition. The possible existence of such quark matter in the cores of massive neutron stars, at ultrarelativistic heavy‐ion collisions and in the early state of the Universe are discussed in a verbal approx

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250407

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

摘要:

AbstractNumerical solutions of a nonlinear system of equations describing the evolution of the strongly dissipative beam‐plasma instability are presented (time or space dependence of the unstable waves, the evolution of the beam distribution function and the corresponding phase space representations are given). Such an instability establishes if the linear growth rate of the unstable waves is small in comparison to the effective collision frequency of the electrons of the dissipative plasma. It is shown that after saturation of the instability there is an efficient energy transfer from the directed motion of the beam electrons to the thermal motion of the plasma electrons. Arguments are given that the strongly dissipative beam‐plasma instability is possibly the basic plasma heating mechanism which operates in the quasi‐stationary state of the beam plasma discharge. Self‐consistent initial conditions are used for the numerical calculations. Formation and evolution of dissipative structures (vortex structure, chaotic structure) were observed. A profound investigation of the chaotic or turbulent beam relaxation mechanism is presented. Such a relaxation mechanism develops in the case of the nonresonant dissipative instability (e.g. in resistive wall‐electron beam amplifiers). The method of investigation of dissipative structures presented in this paper (application of Shannon's information theory and results of the theory of dynamical systems with chaotic behaviour) can be extended to studies of other beam‐plasma systems within the framework of partial kinetic

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250408

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY

ISSN:0005-8025    

DOI:10.1002/ctpp.19850250401

出版商:WILEY‐VCH Verlag    

年代:1985

数据来源: WILEY