Subwavelength resolution imaging of the solar deep interior

Shravan Hanasoge, Thomas L. Duvall

    Research output: Contribution to journalArticle

    Abstract

    We derive expectations for signatures in the measured travel times of waves that interact with thermal anomalies and jets. A series of numerical experiments that involve the dynamic linear evolution of an acoustic wave field in a solarlike stratified spherical shell in the presence of fully three-dimensional time-stationary perturbations are performed. The imprints of these interactions are observed as shifts in wave travel times, which are extracted from these data through methods of time-distance helioseismology (Duvall et al.). In situations where at least one of the spatial dimensions of the scatterer was smaller than a wavelength, oscillatory time shift signals were recovered from the analyses, pointing directly to a means of resolving subwavelength features. As evidence for this claim, we present analyses of simulations with spatially localized jets and sound-speed perturbations. We analyze one year's worth solar observations to estimate the noise level associated with the time differences. Based on theoretical estimates, Fresnel zone time shifts associated with the (possible) sharp rotation gradient at the base of the convection zone are on the order of 0.01-0.1 s, well below the noise level that could be reached with the currently available amount of data (∼0.15-0.2 s with 10 yr of data).

    Original languageEnglish (US)
    Pages (from-to)1678-1685
    Number of pages8
    JournalAstrophysical Journal
    Volume693
    Issue number2
    DOIs
    StatePublished - Mar 10 2009

    Fingerprint

    travel time
    perturbation
    travel
    shift
    acoustic wave
    wave field
    temperature anomaly
    helioseismology
    acoustics
    spherical shells
    convection
    estimates
    shell
    wavelength
    signatures
    anomalies
    simulation
    gradients
    experiment
    scattering

    Keywords

    • hydrodynamics
    • Sun: helioseismology
    • Sun: interior
    • Sun: oscillations
    • waves

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Subwavelength resolution imaging of the solar deep interior. / Hanasoge, Shravan; Duvall, Thomas L.

    In: Astrophysical Journal, Vol. 693, No. 2, 10.03.2009, p. 1678-1685.

    Research output: Contribution to journalArticle

    Hanasoge, Shravan ; Duvall, Thomas L. / Subwavelength resolution imaging of the solar deep interior. In: Astrophysical Journal. 2009 ; Vol. 693, No. 2. pp. 1678-1685.
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