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9
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84951882721
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The present analysis assumes stable electron‐transport parameters dependent only on the local electric field. The validity of this approximation requires that the electrons attain a steady state, with a stable energy‐distribution function, in a linear distance much smaller than either the gas gap for a uniform electric field, or the incremental length for appreciable change in the electric field due to space‐charge distortion. The mean free path in the direction of the electric field is given by [formula omitted] where λ is the mean free path for momentum transfer, [formula omitted] is the electron drift velocity, and [formula omitted] is the average thermal speed of the electrons. Thus, [formula omitted], since [formula omitted] is invariably much smaller than [formula omitted]. For the range of pressures (>300 Torr) encountered in the gas panel, we can estimate [formula omitted] and this leads to [formula omitted] being more than two orders of magnitude smaller than the typical ([formula omitted]) gas gap. This estimate of [formula omitted] is reassuring in that it should lead to a relaxation length for the electron‐distribution function which is much smaller than the gas gap. However, in the event of a strong spatial distortion of the electric field, the local‐field approximation of electron transport may begin to break down in some spatial regions.
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26
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84951897479
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The value of 0. 5 for [formula omitted] assumes that every neon ion leads to an internal secondary electron with sufficient energy to overcome the potential barrier at the surface, but only half of them are emitted in the forward direction to actually escape from the surface.
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27
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84951885664
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The algorithm should also allow for the fact that the electric field can reverse its direction in this low‐field region.
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28
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84951902973
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The calculations with [formula omitted] are done to test the “OFF” state, for which there exists a negligible amount of space charge to distort the electric field. The region [formula omitted] extends to the anode and the computation time is considerably reduced by increasing the upper limit of [formula omitted] to 50 nsec for these calculations.
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30
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84951896029
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The value of [formula omitted] is ignored and not plotted in Fig. 2 for [formula omitted], since the error in dividing these measured quantities increases progressively for small amounts of charge and voltage transfer.
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32
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84951890714
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The minimum sustain voltage [formula omitted] for bistable operation was not calculated since the computation time becomes excessively long for the large number of successive cycles required to reach stability as the amplitude of the applied voltage approaches [formula omitted].
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