Re: Racing sparks, streamer growth, coupling, etc.

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

Original poster: "boris petkovic by way of Terry Fritz <twftesla-at-uswest-dot-net>" <petkovic7-at-yahoo-dot-com>




I don't think that "racing sparks" are related
> directly to coupling.
> >  > When the coupling is increased, there is no
> significant change in the
> >  > maximum dv/dt of the voltage waveforms,
> compared to what would occur
> >  > close to the end of the energy transfer
> proccess with lower coupling.
> >  
> >  Why wouldn't the dv/dt be higher with more
> coupling? (having not done the
> >  calcualtions myself, I am lazy)... I would think
> more energy in the same
> >  time would imply more voltage at the Vpeak, so
> the dv/dt must be higher at
> >  any given time.
> >  
> >  I don't think the dv/dt is much higher with
> better coupling, just that the
> >  max voltage the top load can reach is higher.  
>
----
Antonio,

What is more important that local dv/dx gradients
,along coil structure, during the stage of voltage
buildup are higher tighter coupling.
This in combination with higher final voltage of the
top,especially if smooth electrodes are
employed,contribute to the increased stress of
secondary structure.
----    

 
> Jim, Antonio, all,
> 
> Certainly if the k is tighter, more energy will get
> to the secondary
> and top load, because the losses will be lower due
> mostly to lower
> spark gap losses in a practical coil anyway.
> 
> Regarding big top loads, I do see increasing racing
> sparks with
> larger toploads.
> 
John,
If you use larger smooth electrodes without breaking
point for spark , thing you mentioned  might  occur.
 
Smaller top electrodes emit corrona earlier ,and
althougt theoretical voltage for given input bang
should be higher it is  reduced that way.
Anyway,my opinion is that different distribution of
electrical field around the top due to the presence  
of ion cloud may have impact too (TBD).
 
Regards,
Boris   

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