The current status of analyzing high-degree modes

Johann Reiter, Edward J. Rhodes, Alexander G. Kosovichev, Jesper Schou

Research output: Contribution to journalConference articlepeer-review


One of the most glaring issues in contemporary helioseismology is the rather limited availability of both high-degree mode frequencies for use in inversions of solar internal structure as well as of high-degree frequency splittings for use in inversions of solar internal dynamics. The lack of high-degree frequencies and frequency splittings has occurred because of the inherent difficulties in measuring such frequencies and frequency splittings in high-degree spectra without the inclusion of numerous systematic errors. After the discussion of both the importance and the problems inherent in the analysis of high-degree modes, we describe some fitting methodologies developed since the mid 1990s to obtain high-degree mode characteristics. Finally, we present initial results from the inversion of high-degree modes obtained with our newly developed multiple-peak, tesseral-spectrum method to demonstrate the potential of high-degree modes in the helioseismic probing of the outer-most layers of the Sun. All results reported are based upon data taken by the Michelson Doppler Imager (MDI), which is onboard the Solar and Heliospheric Observatory (SOHO), operating in its full-disk mode during the 1996 Dynamics Run.

Original languageEnglish (US)
Pages (from-to)61-72
Number of pages12
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number559
StatePublished - 2004
Externally publishedYes
EventSOHO 14/GONG 2004 Workshop - Helio- and Asteroseismology: Towards a Golden Future - New Haven, CT, United States
Duration: Jul 12 2004Jul 16 2004

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Space and Planetary Science


  • Methods: Data analysis
  • Sun: oscillations


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