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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