The Solar Oscillations Investigation — Michelson Doppler Imager

  • P. H. Scherrer
  • R. S. Bogart
  • R. I. Bush
  • J. T. Hoeksema
  • A. G. Kosovichev
  • J. Schou
  • W. Rosenberg
  • L. Springer
  • T. D. Tarbell
  • A. Title
  • C. J. Wolfson
  • I. Zayer
  • The MDI Engineering Team

Abstract

The Solar Oscillations Investigation (SOI) uses the Michelson Doppler Imager (MDI) instrument to probe the interior of the Sun by measuring the photospheric manifestations of solar oscillations. Characteristics of the modes reveal the static and dynamic properties of the convection zone and core. Knowledge of these properties will improve our understanding of the solar cycle and of stellar evolution. Other photospheric observations will contribute to our knowledge of the solar magnetic field and surface motions. The investigation consists of coordinated efforts by several teams pursuing specific scientific objectives.

The instrument images the Sun on a 10242 CCD camera through a series of increasingly narrow spectral filters. The final elements, a pair of tunable Michelson interferometers, enable MDI to record filtergrams with a FWHM bandwidth of 94 mÅ. Normally 20 images centered at 5 wavelengths near the Ni I 6768 spectral line are recorded each minute. MDI calculates velocity and continuum intensity from the filtergrams with a resolution of 4" over the whole disk. An extensive calibration program has verified the end-to-end performance of the instrument.

To provide continuous observations of the longest-lived modes that reveal the internal structure of the Sun, a carefully-selected set of spatial averages are computed and downlinked at all times. About half the time MDI will also be able to downlink complete velocity and intensity images each minute. This high rate telemetry (HRT) coverage is available for at least a continuous 60-day interval each year and for 8 hours each day during the rest of the year. During the 8-hour HRT intervals, 10 of the exposures each minute can be programmed for other observations, such as measurements in MDI’s higher resolution (1.25") field centered about 160" north of the equator; meanwhile, the continuous structure program proceeds during the other half minute. Several times each day, polarizers will be inserted to measure the line-of-sight magnetic field.

MDI operations will be scheduled well in advance and will vary only during the daily 8-hour campaigns. Quick-look and summary data, including magnetograms, will be processed immediately. Most high-rate data will be delivered only by mail to the SOI Science Support Center (SSSC) at Stanford, where a processing pipeline will produce 3 Terabytes of calibrated data products each year. These data products will be analyzed using the SSSC and the distributed resources of the co-investigators. The data will be available for collaborative investigations.

Keywords

Modulation Transfer Function Convection Zone Halo Orbit Michelson Doppler Imager Continuum Intensity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Akin, D., Horber, R., and Wolfson, J.: 1993, NASA Conference Publication 3205, 219.Google Scholar
  2. Appourchaux, T., and Andersen, B.N.: 1990, Solar Phys. 128, 91.ADSCrossRefGoogle Scholar
  3. Bogart, R.S., Ferguson, S.H., Scherrer, P.H., Tarbell, T.D., and Title, A.M.: 1988, Solar Phys. 116, 205.ADSGoogle Scholar
  4. Bogart R.S., Sa L.A.D., Duvall T.L. Jr., Haber D.A., Toomre J., and Hill F.: 1995, in V. Domingo, A. Poland, and J.T. Hoeksema (eds.), Proceedings of the 4th SOHO Workshop: Helioseismology, ESA SP-376, in press.Google Scholar
  5. Braun, D.C., Duvall, T.L. Jr., and LaBonte, B.J.: 1988, Astrophys. J. 335, 1015.ADSCrossRefGoogle Scholar
  6. Brown, T.M.: 1980, in R.B. Dunn (ed.), Solar Instrumentation: What’s Next?, National Solar Observatory: Sunspot, NM, 150.Google Scholar
  7. Claverie, A., Isaak, G.R., McLeod, C.P., van der Raay, H.B., and Roca Cortés, T.: 1979, Mature 282, 591.ADSGoogle Scholar
  8. Deubner, F.L.: 1975, Astron. Astrophys. 44, 371.ADSGoogle Scholar
  9. Domingo, V., et al.: 1995, Solar Phys., this issue.Google Scholar
  10. Duvall, T.L. Jr., Harvey, J.W., Jefferies, S.M., and Pomerantz, M.A.: 1991, Astrophys. J. 373, 308.ADSCrossRefGoogle Scholar
  11. Evans, J.W.: 1980, in R.B. Dunn (ed.), Solar Instrumentation: What’s Next?, National Solar Observatory: Sunspot, NM, 155.Google Scholar
  12. Field, G.B., and the Astronomy Survey Committee: 1982, Astronomy and Astrophysics for the 1980’s, National Academy Press: Washington, D.C.Google Scholar
  13. Fröhlich, C., and the VIRGO Team: 1995, Solar Phys., this issue.Google Scholar
  14. Gabriel, A., and the GOLF Team: 1995, Solar Phys., this issue.Google Scholar
  15. Gough, D.O. and Toomre, J.: 1991, Ann. Rev. Astron. Astrophys., 29, Annual Reviews, Inc.: Palo Alto, CA, 627.Google Scholar
  16. Grec, G., Fossat, E., and Pomerantz, M.: 1980, Nature 288, 541.ADSCrossRefGoogle Scholar
  17. Harvey, J., and the GONG Instrument Development Team: 1988, in E.J. Rolfe (ed.), Seismology of the Sun and Sun-Like Stars, ESA: The Netherlands, 203.Google Scholar
  18. Hill, F.: 1988, Astrophys. J. 333, 996.ADSCrossRefGoogle Scholar
  19. Krimigis, S.M., and the Space Science Board Committee on Solar and Space Physics: 1985, An Implementation Plan for Priorities in Solar-System Space Physics, National Academy Press: Washington, D.C.Google Scholar
  20. Kuhn, J.R., Libbrecht, K.G., and Dicke, R.H.: 1987, Nature 328, 326.ADSCrossRefGoogle Scholar
  21. Kuhn J.R., Lin H., and Loranz, D.: 1991, P.A.S.P. 103, 1097.ADSCrossRefGoogle Scholar
  22. Kumar, P., Duvall, T.L. Jr., Harvey, J.W., Jefferies, S.J., Pomerantz, M.A., and Thompson, M.J.: 1990, in Y. Osaki and H. Shibahashi (eds.), Progress of Seismology of the Sun & Stars, Springer-Verlag: Berlin, 87.CrossRefGoogle Scholar
  23. Kumar, P., and Lu, E.: 1991, Astrophys. J. Lett. 375, L35.ADSCrossRefGoogle Scholar
  24. Leibacher, J.W. and Stein, R.F.: 1971, Astrophys. J. Lett 7, 191.Google Scholar
  25. Leighton, R.B., Noyes, R.W., and Simon, G.W.: 1962, Astrophys. J. 135, 474.ADSCrossRefGoogle Scholar
  26. Loefdahl, G. and Scharmer, G.B.: 1994, Astron. Astrophys. Suppl. 107, 243.ADSGoogle Scholar
  27. McWilliams, T. and Kuhn, J.R.: 1992, SOI Technical Note 83, Stanford, CA.Google Scholar
  28. November, L.J., Simon, G.W., Tarbell, T.D., Title, A.M., and Fergusen, S.H.: 1987, in Athay & D.S. Spicer (eds.), Theoretical Problems in High Resolution Solar Physics, NASA Conf. Publ. 2483: Washington, D.C., p. 121.Google Scholar
  29. Noyes, R.W., and Rhodes, E.J. Jr., eds.: 1984, Probing the Depths of a Star: The Study of Solar Oscillations from Space, NASA JPL: Pasadena, CA.Google Scholar
  30. Patrón Recio, D.J.: 1994, Tridimensional Distribution of Horizontal Velocity Flows Under the Solar Surface, Ph.D. Diss., Inst, de Astrofisica de Canarias: La Laguna, Spain.Google Scholar
  31. Rees, D.E. and Semel, M.D.: 1979, Astron. & Astrophys. 74, 1.ADSGoogle Scholar
  32. Rice, R.F.: 1979 in SPIE Symp. Proc207, San Diego, CA.Google Scholar
  33. Schou, J.: 1992, On the Analysis of Helioseismic Data, Ph.D. Dissertation, Aarhus Universitet: Aarhus, Denmark.Google Scholar
  34. Schou, J., Christensen-Dalsgaard, J. and Thompson, M.J.: 1994, Astrophys. J. 433, 389.ADSCrossRefGoogle Scholar
  35. Simon, G.W., Title, A.M., Topka, K.P., Tarbell, T.D., Shine, R.A., Ferguson, S.H., Zirin, H., and the SOUP Team: 1988, Astrophys. J. 327, 367.CrossRefGoogle Scholar
  36. Spruit, H.C., Nordlund, A., and Title, A.M.: 1990, Ann. Rev. Astron. Astrophys. 28, 263.ADSCrossRefGoogle Scholar
  37. Strous, L.H.: 1994, Dynamics in Solar Active Regions: Patterns in Magnetic-Flux Emergence, Ph.D. Dissertation, Universiteit Utrecht: The Netherlands.Google Scholar
  38. Title, A.M. and Ramsey, H.E.: 1980, Applied Optics 19, 2046.ADSCrossRefGoogle Scholar
  39. Title, A.M. and Rosenberg, W.J.: 1979, Applied Optics 18:20, 3443.ADSCrossRefGoogle Scholar
  40. Title, A.M. and Rosenberg, W.J.: 1981, Opt. Eng. 20:6, 815.ADSGoogle Scholar
  41. Title, A.M., Tarbell, T.D., and Simon, G.W.: 1986, Adv. Space Res. 6, 253.ADSCrossRefGoogle Scholar
  42. Title, A.M., Tarbell, T.D., Topka, K.P., Ferguson, S.H., Shine, R.A., and the SOUP Team: 1989, Astrophys. J. 336, 475.ADSCrossRefGoogle Scholar
  43. Ulrich, R.K.: 1970, Astrophys. J. 162, 933.ADSCrossRefGoogle Scholar
  44. Zayer, I., Chapman, I., Duncan, D., Kelley, G., and Mitchell, K.: 1993, in SPIE Symp. Proc., 1900, 97.ADSCrossRefGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • P. H. Scherrer
    • 1
  • R. S. Bogart
    • 1
  • R. I. Bush
    • 1
  • J. T. Hoeksema
    • 1
  • A. G. Kosovichev
    • 1
  • J. Schou
    • 1
  • W. Rosenberg
    • 2
  • L. Springer
    • 2
  • T. D. Tarbell
    • 2
  • A. Title
    • 2
  • C. J. Wolfson
    • 2
  • I. Zayer
    • 2
  • The MDI Engineering Team
  1. 1.W. W. Hansen Experimental Physics LaboratoryCenter for Space Science and Astrophysics, Stanford UniversityStanfordUSA
  2. 2.Lockheed Palo Alto Research LaboratoryPalo AltoUSA

Personalised recommendations