Re: Why ARE the sparks blue / purple (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 28 Oct 2007 16:51:48 -0500
From: Bert Hickman <bert.hickman@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Why ARE the sparks blue / purple (fwd)

Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Sun, 28 Oct 2007 18:34:42 +0000
> From: James Howells <james@xxxxxxxxxxxxxxxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: Why ARE the sparks blue / purple
> 
> At Saturday's CAMBRIDGE ( UK) TESLATHON  I was asked by a visitor why 
> are the sparks blue /purple
> and I did not know !
> I assumed it was because ozone resonates at that optical  wave length 
> but I do not know for sure ..... answers please.
> 

The bluish and purple color of lower current corona and air discharges 
actually comes mainly from vibrationally excited neutral or ionized 
nitrogen molecules. The bright blue-white color of higher current 
(connected) sparks is predominantly from black body (thermal) radiation 
from hot gases in the spark channel.

Bert
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