Re: Cyclotron effect

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

Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>

Paul,

>
>Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
<paul-at-abelian.demon.co.uk>
>
>If a beam of charged particles was launched upwards from the center
>of the toroid, they would continue straight up, unaffected by
>the B field (since beam v x B is zero).
>
>But at any angle from the vertical they would form themselves into
>a spiral (ish) path since v x B is now generally non-zero. If they
>emerged horizontally from the toroid, they would curve either
>upwards or downwards depending on the sign of their charge and the
>B field polarity (assuming here that E is roughly radial from the
>topload).
>
>Could this cyclotron mechanism also affect the path over which a
>streamer forms?  Do the electrons in the leaders see a sufficient
>v x B force to make a noticeable difference to their path?


The story I get when I ask about "spark formation" is that they grow in
nano-seconds (when the E field is strongest?), whereas the E field and
the B field have a period measured in micro-seconds, three orders of
magnitude different. And the B and E fields are 90-degrees out of phase,
so that when the E field is max the B field is zero (I'm assuming the
energy is entirely in the secondary at this point, so only secondary E,B,
not primary E,B which are phased even more differently, are relevant).
Finally the spiral sparks I've observed have a duration of thousands of 120-Hz
periods (another three orders of magnitude in time), clearly a case of sparks
retracing the path of earlier sparks.

One question is, do the sparks "spiral" during the nanoseconds that they
exist, or is it that the next spark 120-th of a second later takes a path
that is a little different from the previous, leading to the optical
illusion of a continuously arcing spiraling spark.


On the other hand, I've observed "meandering S" sparks inside various "plasma
sphere" type displays, and I wonder if these meandering S sparks are related
to the spiral sparks others (and occasionally myself also) have seen. The
"S"s I'm talking about are like the Oxbow meandering of a river, a slight
deviation from straight seems to amplify itself into a hugh loop, and it
seems as though a similar pattern (though by an as yet unknown process) is
happening in these plasma spheres. 

So I am wondering if the sparks spiral based on their own self induced mag
fields? Obviously this cannot happen for a perfectly straight spark, but
for one that starts out initially slightly curved, could its own mag field
cause the curve to be amplified? It seems that the answer is "maybe", two
parallel conductors with parallel current repel, but with anti-parallel
current they attract. The far ends of a spark that is slightly curved are
slightly anti-parallel, and so they attract each other - causing an initial
very slight "S" shape to amplify into an exagerated "S".

So this might be an explanation for "S" curves in a plane, does this explain
"spiral" sparks. Maybe spiral sparks are the result of a combination of
thermal convection and exagerated "S" curves. Or maybe some more thinking is
required...


>
>Can this account for the observed spiral discharges?
>
>Assuming electrons are the sole candidates for being affected (due
>to their lightness and relative mobility compared to the ionised
>atoms) we should see the spirals form in opposite directions on
>alternate half cycles, due to reversal of B.
>
>Do the observed spirals appear to rotate both ways?
>
>For an order of magnitude we can easily put forward a value for B,
>but does anyone have a guess for v?
>
>If the spiral streamers tend to be entirely or mostly in one
>direction does that direction reverse if you replace the secondary
>with an identical one wound in the opposite direction?


and if this conversation were taking place in the hanggliding list we'd
have to discus the Corriolis effect, and wonder if sparks spiral the same
way in the northern verses the southern hemisphere! :-)))) - just kidding!


>
>If the toroid is connected to another smaller toroid, displaced some
>way to the side of the coil, such that the streamers relocate to it,
>do they retain the spiral effect?
>
>A couple of experiments there to add to the ever expanding list.
>
>Is it worth computing the trajectory of a charged particle leaving
>the toroid?  We know E and B for the region, but what about v? 
>
>And has anyone used one of those little NIB magnets as a breakout
>point?  Wrapped in foil perhaps?
>--
>Paul Nicholson
>--
>
>
>

So I'm torn between wanting to believe that spiral sparks are mostly a
convection phenomenon, verses the meandering S sparks in some (not all)
plasma spheres are perhaps a similar phenomenon but are probably not caused
by convection since they are in an almost vacuum.


so many things to figure out, so little time...
-Peter Lawrence.


(ps, I really liked reading your recent post to Antonio, I appreciate the
explanations in terms of discrete sumations better than the calculus
formulations of integrals over differentials (is it any wonder that I'm a
computer programmer, not a physicist). This gives me a better intuition
about Cee,Ces,Lee,Les than your tssp paper, even though other folks will
appreciate the paper more.)