[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Streamer simulation
Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net>
Jim and Antonio,
Lightning, Lichtenberg Figures, and streamers all appear to be forms of
fractals that seem to be characterized by Diffusion Limited Aggregation
(DLA). For an example of a computer model that uses a DLA algorithm to
model growth to form a Lichtenberg Figure before your eyes, check out:
http://apricot.ap.polyu.edu.hk/~lam/dla/dla.html
Per the author, the algorithm is very simple: "We start with an immobile
seed on the plane. A walker is then launched from a random position far
away and is allowed to diffuse. If it touches the seed, it is immobilized
instantly and becomes part of the aggregate. We then launch similar walkers
one-by-one and each of them stops upon hitting the cluster. After launching
a few hundred particles, a cluster with intricate branch structures results."
You can see the shallow angles (mentioned by Dr. Resonance in a previous
post) formed between most of the branches in this model as well.
Best regards,
-- Bert --
--
--------------------------------------------------------------------
We specialize in UNIQUE items! Coins shrunk by Ultrastrong Fields,
Lichtenberg Figures (electrical discharges in acrylic), & Scarce OOP
Technical Books. Stoneridge Engineering -- http://www.teslamania-dot-com
--------------------------------------------------------------------
Tesla list wrote:
>Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Monday, September 22, 2003 6:29 PM
>Subject: Re: Streamer simulation
>
> > Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> >
> > Tesla list wrote:
> > >
> > > Original poster: Jim Lux <jimlux-at-earthlink-dot-net>
> > >
> > > I don't know that a fractal model is optimum (streamer development
>isn't
> > > scale independent, like fractals are), but some sort of cellular
>automata
> > > model might be...
> >
> > Journal of Physics D: Applied Physics 34 (2001) 936-946.
> > "Simulation of breakdown in air using cellular automata with streamer
> > to leader transition".
> > Has nice plots of simulated streamers. The references mention several
> > papers about the fractal nature of streamers.
>I see that my random thoughts have been anticipated...
> >
> > > Essentially, you've got chunks of air that are in one of three
>states...
> > > nothing, streamer growing, and streamer fully formed, and then they get
> > > connected in an essentially random (tree structured) way. The physics
> > > going on at the tip of the streamer is pretty much the same, whether
>it's
> > > at the end of a 10cm streamer or a 1m streamer. Likewise, what's going
>on
> > > inside the developed streamer is essentially the same regardless of
>where
> > > along the streamer it is.
> >
> > The idea in the paper appears to be similar.
>I'll have to get it tomorrow at work...
>The cellular automata thing is nifty because it can be made very
>computationally efficient (as opposed to a big FEM grid or a 2.5 D sim)
>
>.