Regime Controlled by Electron-Ion Recombination

If the moderate or high-pressure gas is not electronegative, the volume balance of electrons and positive ions can be reduced to the simple ionization-recombination balance. In electronegative gases, however, two qualitatively different self-sustained regimes can be achieved (at different effectiveness of electron detachment) one controlled by recombination and another controlled by electron attachment. 

In some plasma-chemical systems, the destruction of negative ions by, for example, associative electron detachment is faster than ion-ion recombination  

In this case, actnal losses of charged particles are also due to electron-ion recombination, in the same way as non-electronegative gases. Such a situation can take place, in particular. 

The parameter 5- = k /k shows the detachment ability that compensates for electron losses dne to attachment. If 5- 1, the attachment inflnence is negligible and kinetic equation (4-21) becomes eqnivalent to one for non-electronegative gases. The kinetic equation inclndes the effective rate coefficients of ionization, kf = kj + g, and recombination, k f = kf + gk. Eqnation (4-21) describes electron density evolution to the steady-state magnitnde of the recombination-controlled regime  

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