2008/09/30 by S. Tanveer, Saleh Tanveer, Lothar Schäfer +3
Engineering · Physics and Astronomy · #Lightning and Electromagnetic Phenomena #Power Transformer Diagnostics and Insulation #Theoretical and Computational Physics #nlin.PS
paper · pdf · doi:10.1016/j.physd.2009.02.012
published as Physica D 238, 888-901 (2009) · 37 pages, 6 figures, revised for Physica D
arxiv created 2009/02/17 · openalex publication_date 2009/03/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
An interfacial approximation of the streamer stage in the evolution of sparks and lightning can be written as a Laplacian growth model regularized by a `kinetic undercooling' boundary condition. We study the linear stability of uniformly translating circles that solve the problem in two dimensions. In a space of smooth perturbations of the circular shape, the stability operator is found to have a pure point spectrum. Except for the zero eigenvalue for infinitesimal translations, all eigenvalues are shown to have negative real part. Therefore perturbations decay exponentially in time. We calculate the spectrum through a combination of asymptotic and series evaluation. In the limit of vanishing regularization parameter, all eigenvalues are found to approach zero in a singular fashion, and this asymptotic behavior is worked out in detail. A consideration of the eigenfunctions indicates that a strong intermediate growth may occur for generic initial perturbations. Both the linear and the nonlinear initial value problem are considered in a second paper.