EntityQ1303846· pop 13· linked from 23 articlesEikonal equationSign in to savenon-linear partial differential equation encountered in problems of wave propagationConnectionsgeometrical opticsEntityWKB approximationEntityInternational Standard Book NumberEntityAncient GreekEntitywaveEntitydigital object identifierEntityelectric fieldEntityoceanographyEntityMaxwell's equationsEntityWilliam Rowan HamiltonEntityFields medalEntitySchrödinger equationEntitycausalityEntityQ180686Entityrefractive indexEntityJSTOREntityEuclidean spaceEntitygradientEntitybibcodeEntityVladimir ArnoldEntityCategoriesGeometrical opticsNonlinear partial differential equations