ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We present a simulation of the breakdown stage of high-power, short-pulse high-frequency discharges in hydrogen, produced when an electric field of the form E(t)=EmaxIW(1−e−t/τ)sin(ωt) is applied to a cylindrical resonant cavity. Typical discharge operating conditions considered are applied powers 1–15 kW, gas pressures 0.1–20 Torr, cavity diameter of 25.71 cm, tube radius of 0.8 cm, field frequency ω/2π=1.12 GHz, pulse width tP=10 μs, and rising times τ of a few microseconds. Under these conditions, discharge breakdown occurs before the electric field reaches its maximum amplitude EmaxIW, this situation corresponding to the so-called increasing wave (IW) regime. The simulation is based on a Monte Carlo model to calculate the breakdown times, tb, and fields, Eb, for different field rising slopes EmaxIW/τ(similar, equals)10−1−103 V cm−1 ns−1. The results obtained show that a breakdown criterion based on the electron energy balance (cursive-epsilongain=cursive-epsilonloss, where cursive-epsilongain and cursive-epsilonloss are, respectively, the mean electron energy gain and loss) yields excellent agreement between calculated and measured values of tb and Eb, while the classical particle rate balance criterion (νgain=νloss, where νion and νloss are, respectively, the mean electron production and loss frequencies) is satisfied only at pressures below 0.5 Torr. It is further shown that: (i) the IW limit for long breakdown times (tb(similar, equals)τ→∞) corresponds to the continuous wave regime; and (ii) there is an equivalence between pulsed excitation, with pulse width tP, and IW regimes, for short breakdown times such that tb=tP(very-much-less-than)τ. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1288510
Permalink
