Abstract
A time series of GONG Dopplergrams for the period 10–14 May 1997 from Udaipur and Big Bear sites has been used to measure the velocity fluctuations in a sunspot (NOAA active region 8038) and quiet photosphere simultaneously. We observe that the power of pre-dominant p mode is reduced in the sunspot as compared to quiet photosphere by 39–52% depending on the location of the sunspot region on the solar disk. We also observe a relative peak frequency deviation of p modes in the sunspot, of the order of 80–310 μHz, which shows a linear dependence on the magnetic field gradient in the active region. The maximum frequency deviation of 310 μHz on 12 May appears to be an influence of a long-duration solar flare that occurred in this active region. We interpret this relative peak frequency deviation as either due to power re-distribution of p modes in the sunspot or a consequence of frequency modulation of these modes along the magnetic flux tubes due to rapidly varying magnetic field structure.
Similar content being viewed by others
References
Anderson, E. R., Duvall, Jr., T. L., and Jeffries, S. M.: 1990, Astrophys. J. 364, 699.
Balthasar, H., Martinez Pillet, V., Schleicher, H., and Wöhl, H.: 1998, Solar Phys. 182, 65.
Beckers, J. M. and Schultz, R. B.: 1972, Solar Phys. 27, 61.
Bhatnagar, A., Livingston, W. C., and Harvey, J. W.: 1972, Solar Phys. 27, 80.
Bogdan, T. J., Brown, T. M., Lites, B. W., and Thomas, J. H.: 1993, Astrophys. J. 406, 723.
Braun, D. C. and Duvall, Jr., T. L.: 1990, Solar Phys. 129, 83.
Braun, D. C., Duvall, Jr., T. L., and LaBonte, B. J.: 1987, Astrophys. J. 319, L27.
Braun, D. C., Duvall, Jr., T. L., and LaBonte, B. J.: 1988, Astrophys. J. 335, 1015.
Braun, D. C., Duvall, Jr., T. L., LaBonte, B. J., Jefferies, S. M., Harvey, J. W., and Pomerantz, M. A.: 1992, Astrophys. J. 391, L113.
Cally, P. S.: 1995, Astrophys. J. 451, 372.
Giovanelli, R. G. and Slaughter, C.: 1978, Solar Phys. 57, 255.
Harvey, J. et al.: 1996, Science 272, 1284.
Hindman, B. W. and Brown, T. M.: 1998, Astrophys. J. 504, 1029.
Horn, T., Staude, J., and Landgraf, V.: 1997, Solar Phys. 172, 69.
Jain, R. and Tripathy, S. C.: 1998, Solar Phys. 181, 113.
Jain, R. et al.: 1999, Astrophys. J. (submitted)
Kentischer, T. J. and Mattig, W.: 1995, Astron. Astrophys. 300, 539.
Keppens, R.: 1994, in Roger. K. Ulrich, Edward J. Rhodes, Jr., and Werner Dappen (eds), GONG '94: Helio-and Asteroseismology from the Earth and Space, A.S.P. Conference Series, p. 250.
Lites, B. W., White, O. R., and Packman, D.: 1982, Astrophys. J. 253, 386.
Livingston, W. C. and Mahaffey, C.: 1981, in Lawrence E. Cram and John H. Thomas (eds), The Physics of Sunspots, (Sac Peak Observatory conference proceedings 14-17 July, 1981), p. 312.
Nye, A. H., Cram, L. E., Thomas, J. H., and Beckers, J. M.: 1981, in Lawrence E. Cram and John H. Thomas (eds), The Physics of Sunspots (Sac Peak Observatory Conference Proceedings, 14-17 July, 1981), p. 313.
Press, W. H., Teukolsky, S. A., Vellerling, W. T., and Flannery, B. P.: 1992, Numerical Recipies in FORTRAN, Cambridge University Press, Cambridge, p. 644.
Rice, J. B. and Gaizauskas, V.: 1973, Solar Phys. 32, 421.
Soltau, D., Schroter, E. H., and Wöhl, H.: 1976, Astron. Astrophys. 50, 367.
Tarbell, T. D., Peri, M., Frank, Z., Shine, R., and Title, A.: 1988, in V. Domingo and E. J. Rolfe (eds), Seismology of the Sun and Sun-like Stars, ESA SP-286, p. 315.
Title, A. M., Topka, K. P., Tarbell, T. D., Schmidt, W., Balke, C., and Scharmer, G.: 1992, Astrophys. J. 393, 782. ??
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Kumar, B., Jain, R., Tripathy, S. et al. p Modes in and Away from a Sunspot. Solar Physics 191, 293–307 (2000). https://doi.org/10.1023/A:1005209623215
Issue Date:
DOI: https://doi.org/10.1023/A:1005209623215