Aachen PK 2003 – wissenschaftliches Programm

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P: Plasmaphysik

P 4: Poster I

P 4.4: Poster

Montag, 17. März 2003, 17:45–19:15, Foyer

A numerical investigation of growing and branching discharge streamers — •Carolynne Montijn, Willem Hundsdorfer, Andrea Rocco, and Ute Ebert — CWI, Kruislaan 413, 1098 SJ Amsterdam, The Netherlands

We investigate the “minimal streamer model”: a local continuum approximation for electric breakdown. The model is strongly nonlinear due to space charge effects. After the avalanche to streamer transition, this nonlinearity creates an ionized and a non-ionized phase separated by a rapidly propagating ionization front.

We present simulations in effectively 2D (i.e., in 3D with radial symmetry). They show that for a sufficiently high applied field, after the avalanche to streamer transition, there can be a second transition towards the Lozansky-Firsov limit of streamers where the streamer can branch spontaneously, according to a Laplacian instability quite like in viscous fingering [1,2,3].

Detailled numerical investigations of the very steep ionization fronts ask for adaptive grid methods. These are intricate because of the “pulled” nature of the fronts. We present our solution to this challenge.

[1] M. Arrayás, U. Ebert, W. Hundsdorfer, PRL 88, 174502 (2002).

[2] A. Rocco, U. Ebert, W. Hundsdorfer, PRE 66, 035102(R) (2002).

[3] cf. talk U. Ebert and poster B. Meulenbroek, A. Rocco, U. Ebert.