The energetic conditions in a striated electric discharge

1561. Investigation of the fast striations in prebreakdown of a gas discharge using microwave receiver techniques

“…Oleson using a different approach particularly in the problem of ion production and loss [40] It is obvious that this analysis, even though it considers most of the processes occuring in the discharge, does not lead to any quantitative explanation of the observations on striations, nor does it give any clues as to the origin or the temporal growth of striations » The latter prcb= lems are analysed fully in a series of papers by Pekarek [21,22,23,26,27,28], They are briefly discussed in the following pages.…”

“…Each striation thus has a certain life-time which, as is obvious from the figure that actually corresponds to the situation found experimentally, is greater for striations at a greater distance from the cathode which were thus pro duced later. The electron temperature in the v-th region is denoted by TyCt) = Tg + 0^(t) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) where is the temperature in a homogeneous unstriated column. Similarly the concentration of ions is represented by Ny(t) -+ n^(t) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) and that of the metastable atoms by M^(t) = + m^(t), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) where again and are values of the appropriate concentrations at a homogeneous unstriated column.…”

“…The formulation of the problem leads to an equation of 18th degree in k, the phase constant of the striation modes, which, if it were pos sible to solve, would lead to solutions of the frequency of the various modes of striation observed by Donahue and Dieke, Although the analysis qualitatively explains the existence of the modes, it gives no quantative explanation of the observations on striations, nor does it give any clues as to the origin or the temporal growth of striations, Pekarek, in a series of papers [21][22][23][24][25][26][27][28] tackles the latter problems theoretically and experi mentally, For his v/ork he uses the method of artificially perturbing the plasma of the positive column and observing the propagation of what he calls, the wave of stratification. The results of his final analysis are in close agreement with his experimental observations under typical conditions.…”

“…In this respect extensive investigations have been made by Pekarek [21][22][23][24][25][26][27][28] who studied the growth of striations by introducing an external perturbation at the cathode end of a homogeneous unstriated positive column which gave rise to the production of what he called the wave of stratification» In an analysis intended to justify this observation, Pekarek initially formalized the problem [23] which led to a solution that qualitatively pre= dieted the existence of the wave of stratification»…”