Re: Spark-gap sparks vs. solid-state sparks

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jimlux-at-earthlink-dot-net>


> For a riveting account of such a use of inertia, read Richard Rhodes'
> "Dark Sun", about the making of the hydrogen bomb.  In Chapter 24, Rhodes
> provides a microsecond-by-microsecond account--complete with construction
> diagrams--of the process by which the better part of 82 tons of solid,
> gaseous and liquid material was turned into photons in the space of a few
> microseconds.  It was only possible because of the inertia of its
> components: they stayed together long enough for the numerous consecutive
> nuclear processes to occur.
There are a few technical inaccuracies in Rhodes' description, but none that
materially affect his description... For those looking for a more detailed
look, the "High Energy Weapons Archive" (do a web search, or look at the
mirror site at http://www.fas-dot-org/ ) has much useful info on this. And, of
course, the famous article in "The Progressive" might be of interest (not on
line, to my knowledge). FWIW, the description in "The Sum of all Fears" (Tom
Clancy novel) is probably quite inaccurate.

>
> I see now that the challenge for s.s. designers such as myself lies in
> attempting to emulate, to a degree at least, the rate-of-rise capability
> of the common, garden-variety 19th-century spark-gap.  One has to chase
> that spark and well-overtake it, so to speak.

That spark gap is not such a bad switch.... hence the popularity of various
and sundry forms of spark gap switches in modern equipment, ranging from
welders (HF arc stabilizers) to plasma physics experiments (Z machine).  I
once had a discussion with Jim Corum about the inefficiency (my words) of
the spark gap in a TC.  After thrashing out all the various factors, a spark
gap doesn't compare all that bad to  most tube or SS circuits, considered
for wall plug watts in to RF out.  OTOH, if you are trying to produce a
narrow band or modulated signal, then the VT or SS approach wins, hands
down.