title: Theory of Thomson scattering in inhomogeneous media.
abstract: Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the probing time. On the other hand, laboratory plasmas are seldom uniform and homogeneous on the temporal and spatial dimensions over which data is collected. This is particularly true for laser-produced high-energy-density matter, which often exhibits steep gradients in temperature, density and pressure, on a scale determined by the laser focus. Here, we discuss the modification of the cross section for Thomson scattering in fully-ionized media exhibiting steep spatial inhomogeneities and/or fast temporal fluctuations. We show that the predicted Thomson scattering spectra are greatly altered compared to the uniform case, and may lead to violations of detailed balance. Therefore, careful interpretation of the spectra is necessary for spatially or temporally inhomogeneous systems.
authors.affiliation: Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
authors.forename: P M
authors.initials: PM
authors.lastname: Kozlowski
authors.affiliation: Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.|AWE plc, Reading RG7 4PR, United Kingdom.
authors.forename: B J B
authors.initials: BJ
authors.lastname: Crowley
authors.affiliation: Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: D O
authors.initials: DO
authors.lastname: Gericke
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623, United States.
authors.forename: S P
authors.initials: SP
authors.lastname: Regan
authors.affiliation: Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Gregori