Abstract
In the meridional half plane Π, the capacity relative to some elliptic operators L(≡ L k ) of slender ([2]) line-segments Λ lying on or or parallel to oz and centered on or is considered. We obtain that if ε is small enough (where for some a > 0, 2aε denotes the length of Λ), then CapL(Λ) = O(1/(a k log 1/ɛ)). This is used to estimate the diameter of the cross-section for some axi-symmetric free-boundary elliptic problems. This can apply to some steady vortex rings and plasma problems.
Résumé
Le but de cet article est d'estimer la capacité d'un pétit segment [a(1−ε), a(1+ε)]×{z=0} du démi-plan П := {x = (r, z)|r > 0, z ∈ ℝ} de ℝ2 par rapport à la capacité définie par la norme \(\left\| u \right\|_{H_L }^2 = \int_\prod u Lu r dr dz: = \int_\prod \{ u_r^2 + u_z^2 \} r^{ - k} dr dz\). Ce résultat est ensuite utilisé pour estimer le diamètre de la surface libre de certains problèmes elliptiques non linéaires.
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Tadie Problèmes elliptiques à frontière libre axi-symétriques: Estimation du diamètre de la section au moyen de la capacité. Potential Anal 5, 61–72 (1996). https://doi.org/10.1007/BF00276697
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DOI: https://doi.org/10.1007/BF00276697