Re: The science behind streamer sounds

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

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bert.hickman-at-aquila-dot-net>

Hi Brett,

The sounds made by sparks, streamers, and thunder are all related. All 
are a result of sudden superheating of gas inside the spark channel. The 
  expanding spark channel creates a cylindrical shock wave which then 
rapidly converts into a normal impulsive sound wave (bang!). The amount 
of sound energy generated is a function of the amount of energy being 
dissipated in the discharge and the length of the discharge - more 
energy going into a discharge means a louder "crack". The sound can 
range from a barely audible click from a static electricity discharge, 
the deafening crack of a HV capacitor discharge, the repetitive snapping 
sounds of air streamers from a Tesla Coil, the louder (more energetic) 
bangs of streamers that reach ground, to the defining report of a nearby 
lightning strike. Large Tesla Coils can easily generate streamer noise 
sufficient to damage your hearing.

There's is actually some debate about the exact mechanisms that create 
the shock wave associated with sparks. It is NOT the collapse of the 
superheated spark channel (as once was thought for lightning), but is 
more likely the extremely rapid formation of a high current channel that 
causes the initial shock wave.

Best regards,

-- Bert --
-- 
Bert Hickman
Stoneridge Engineering
"Electromagically" (TM) Shrunken Coins!
http://www.teslamania-dot-com

Tesla list wrote:
> Original poster: "Brett Miller by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <brmtesla-at-yahoo-dot-com>
> 
> All,
> 
> I was showing my father a video tape of my 6 inch
> system running and he asked about what the exact
> mechanism is that creates the sounds the streamers
> make.  I thought about it for a while, but wasn't able
> to give a satisfactory answer.  It's funny, if he had
> asked me about quenching, ringups, or resonance I
> would have talked for an hour.  It's just those basic
> questions of scientific curiosity that can sometimes
> leave us stumped.  Maybe Paul (Nicholson), will have
> something to say here.  Terry?  Anyone?  Thanks.
> 
> -Brett
> 
> 
> 
>