It looks really interesting, but I've never been able to photograph it. Not wanting to get any electronic camera too close. The air in this case is in a closed tube, so there's no external disturbance, but I imagine a pretty good ion wind. On Thu, Apr 2, 2015 at 6:09 PM, Jason White < whitewaterssoftwareinfo@gmail.com> wrote: > The following is speculation: > > * Perhaps those are higher resistance (drier) zones in the air. > Increased resistance could lead to increased heating, > > * Conversely, air that has been heated by the arc into plasma is > highly conductive, perhaps the low resistance of the plasma "funnels" > the arc into hot zones causing localized heating (bright spots). > Perhaps the arc is more spread out outside of these bright spots > resulting in less localized heating (and a less visible arc). > > > > On Thu, Apr 2, 2015 at 7:52 PM, David VanHorn wrote= : > > Something that I've been wondering about, as I look at high voltage > sparks. > > > > Within a single spark, along its length, there are sometimes zones that > are > > much brighter than the rest of the spark. A given spark might have thr= ee > > or four of these, or none. > > > > Any ideas what causes this? Could it be my eye rather than the spark? > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > -- > Jason White > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .