{ "id": "1510.08209", "version": "v1", "published": "2015-10-28T07:00:17.000Z", "updated": "2015-10-28T07:00:17.000Z", "title": "On finding an obstacle with the Leontovich boundary condition via the time domain enclosure method", "authors": [ "Masaru Ikehata" ], "comment": "32pages", "categories": [ "math.AP", "math-ph", "math.MP" ], "abstract": "An inverse obstacle scattering problem for the wave governed by the Maxwell system in the time domain, in particular, over a finite time interval is considered. It is assumed that the electric field $\\mbox{\\boldmath $E$}$ and magnetic field $\\mbox{\\boldmath $H$}$ which are solutions of the Maxwell system are generated only by a current density at the initial time located not far a way from an unknown obstacle. The obstacle is embedded in a medium like air which has constant electric permittivity $\\epsilon$ and magnetic permeability $\\mu$. It is assumed that the fields on the surface of the obstacle satisfy the impedance-or the Leontovich boundary condition $\\mbox{\\boldmath $\\nu$}\\times\\mbox{\\boldmath $H$} -\\lambda\\,\\mbox{\\boldmath $\\nu$}\\times(\\mbox{\\boldmath $E$}\\times\\mbox{\\boldmath $\\nu$})=\\mbox{\\boldmath $0$}$ with $\\lambda$ an unknown positive function and $\\mbox{\\boldmath $\\nu$}$ the unit outward normal. The observation data are given by the electric field observed at the same place as the support of the current density over a finite time interval. It is shown that an indicator function computed from the electric fields corresponding two current densities enables us to know: the distance of the center of the common spherical support of the current densities to the obstacle; whether the value of the impedance $\\lambda$ is greater or less than the special value $\\sqrt{\\epsilon/\\mu}$.", "revisions": [ { "version": "v1", "updated": "2015-10-28T07:00:17.000Z" } ], "analyses": { "subjects": [ "35R30", "35L50", "35Q61", "78A46", "78M35" ], "keywords": [ "time domain enclosure method", "leontovich boundary condition", "current density", "finite time interval", "electric field" ], "note": { "typesetting": "TeX", "pages": 32, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv151008209I" } } }