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Solar Physics

, 294:26 | Cite as

Characteristics of the Solar Coronal Line Profiles from Fabry–Perot Interferometric Observations

  • Maya PrabhakarEmail author
  • K. P. Raju
  • T. Chandrasekhar
Article

Abstract

This article reports the analysis of a set of Fabry–Perot interferograms that were studied to probe the physical parameters of the inner solar corona. The observations were carried out in the coronal green line, Fe xiv 5302.86 Å, during the total solar eclipse of 21 June 2001 that occurred in Lusaka, Zambia. The study was performed in the radial range of \(1.1\,\mbox{--}\,1.5~\text{R}_{\odot}\) and examines the Doppler velocity, half-width, centroid, and asymmetry and their correlations with each other at various points in the corona. We found that 59% of the line profiles are blueshifted, 34% are single components, and only 7% are redshifted. The variations in half-width and Doppler velocity with respect to coronal height have a large scatter and show no significant changes. We found that the variation in half-width with Doppler velocity or centroid follows a parabolic trend with a weak correlation, whereas the relation between half-width and asymmetry is inconclusive. These results may provide more insight into the coronal dynamics and help in understanding the physical problems in the corona.

Keywords

Corona, E Eclipse observations Spectral line, broadening Spectrum, visible 

Notes

Acknowledgements

The authors would like to thank the reviewer for their valuable comments and suggestions. Maya Prabhakar would like to thank the Women Scientist Scheme-A (WOS-A) of the Department of Science & Technology for providing financial support to carry out this project. This work is also funded by the Department of Science & Technology and by the Department of Space, Government of India.

Disclosure of Potential Conflicts of Interest

The authors declare that they have no conflicts of interest.

References

  1. Beck, C., Rezaei, R., Puschmann, K.G., Fabbian, D.: 2016, Spectroscopy at the solar limb: II. Are spicules heated to coronal temperatures? Solar Phys. 291, 2281. DOI. ADS. ADSCrossRefGoogle Scholar
  2. Brekke, P., Hassler, D.M., Wilhelm, K.: 1997, Doppler shifts in the quiet-Sun transition region and corona observed with SUMER on SOHO. Solar Phys. 175, 349. DOI. ADS. ADSCrossRefGoogle Scholar
  3. Brooks, D.H., Warren, H.P.: 2012, The coronal source of extreme-ultraviolet line profile asymmetries in solar active region outflows. Astrophys. J. Lett. 760, L5. DOI. ADS. ADSCrossRefGoogle Scholar
  4. Bryans, P., Young, P.R., Doschek, G.A.: 2010, Multiple component outflows in an active region observed with the EUV imaging spectrometer on Hinode. Astrophys. J. 715, 1012. DOI. ADS. ADSCrossRefGoogle Scholar
  5. Brynildsen, N., Kjeldseth-Moe, O., Maltby, P.: 1995, Quiet-sun connection between intensity, Doppler shift, and line broadening in solar ultraviolet emission lines. Astrophys. J. Lett. 455, L81. DOI. ADS. ADSCrossRefGoogle Scholar
  6. Chae, J., Yun, H.S., Poland, A.I.: 1998, Temperature dependence of ultraviolet line average Doppler shifts in the quiet Sun. Astron. Astrophys. Suppl. Ser. 114, 151. DOI. ADS. ADSCrossRefGoogle Scholar
  7. Chandrasekhar, T., Ashok, N.M., Desai, J.N., Pasachoff, J.M., Sivaraman, K.R.: 1984, Fabry–Perot interferometric observations of the coronal red and green lines during the 1983 Indonesian eclipse. Appl. Opt. 23, 508. DOI. ADS. ADSCrossRefGoogle Scholar
  8. Chandrasekhar, T., Desai, J.N., Ashok, N.M., Pasachoff, J.M.: 1991, Fabry–Perot line profiles in the 5303 A and 6374 A coronal lines obtained during the 1983 Indonesian eclipse. Solar Phys. 131, 25. DOI. ADS. ADSCrossRefGoogle Scholar
  9. Dadashi, N., Teriaca, L., Solanki, S.K.: 2011, The quiet Sun average Doppler shift of coronal lines up to 2 MK. Astron. Astrophys. 534, A90. DOI. ADS. ADSCrossRefGoogle Scholar
  10. De Pontieu, B., McIntosh, S.W., Hansteen, V.H., Schrijver, C.J.: 2009, Observing the roots of solar coronal heating – in the chromosphere. Astrophys. J. Lett. 701, L1. DOI. ADS. ADSCrossRefGoogle Scholar
  11. Delone, A.B., Makarova, E.A.: 1969, Interferometric investigation of the red and green coronal lines during the total solar eclipse of May 30, 1965. Solar Phys. 9, 116. DOI. ADS. ADSCrossRefGoogle Scholar
  12. Delone, A.B., Makarova, E.A.: 1975, Interferometric investigation of the line of sight velocities in the 5303-A line during the eclipse 11 September, 1968. Solar Phys. 45, 157. DOI. ADS. ADSCrossRefGoogle Scholar
  13. Delone, A.B., Makarova, E.A., Yakunina, G.V.: 1988, Erratum: “Evidence for moving features in the corona from emission line profiles observed during eclipses” [J. Astrophys. Astron. 9(1), 41 – 47 (1988)]. J. Astrophys. Astron. 9, 125. DOI. ADS. ADSCrossRefGoogle Scholar
  14. McIntosh, S.W., Tian, H., Sechler, M., De Pontieu, B.: 2012, On the Doppler velocity of emission line profiles formed in the “coronal contraflow” that is the chromosphere-corona mass cycle. Astrophys. J. 749, 60. DOI. ADS. ADSCrossRefGoogle Scholar
  15. Mierla, M., Schwenn, R., Teriaca, L., Stenborg, G., Podlipnik, B.: 2008, Analysis of the Fe X and Fe XIV line width in the solar corona using LASCO-C1 spectral data. Astron. Astrophys. 480, 509. DOI. ADS. ADSCrossRefGoogle Scholar
  16. Patsourakos, S., Klimchuk, J.A.: 2006, Nonthermal spectral line broadening and the nanoflare model. Astrophys. J. 647, 1452. DOI. ADS. ADSCrossRefGoogle Scholar
  17. Peter, H.: 2010, Asymmetries of solar coronal extreme ultraviolet emission lines. Astron. Astrophys. 521, A51. DOI. ADS. ADSCrossRefGoogle Scholar
  18. Peter, H., Judge, P.G.: 1999, On the Doppler shifts of solar ultraviolet emission lines. Astrophys. J. 522, 1148. DOI. ADS. ADSCrossRefGoogle Scholar
  19. Prabhakar, M., Raju, K.P., Chandrasekhar, T.: 2013, Analysis of the solar coronal green line profiles from eclipse observations. In: International Symposium on Solar-Terrestrial Physics, Astronomical Society of India Conference Series 10. ADS. Google Scholar
  20. Prasad, S.K., Singh, J., Banerjee, D.: 2013, Variation of emission line width in mid- and high-latitude corona. Solar Phys. 282, 427. DOI. ADS. ADSCrossRefGoogle Scholar
  21. Raju, K.P.: 1999, The effect of mass motions inside the coronal loops on emission line profiles. Solar Phys. 185, 311. DOI. ADS. ADSCrossRefGoogle Scholar
  22. Raju, K.P., Chandrasekhar, T., Ashok, N.M.: 2011, Analysis of coronal green line profiles: Evidence of excess blueshifts. Astrophys. J. 736, 164. DOI. ADS. ADSCrossRefGoogle Scholar
  23. Raju, K.P., Desai, J.N., Chandrasekhar, T., Ashok, N.M.: 1993, Line-of velocities observed in the inner solar corona during the total solar eclipses of 1980 and 1983. Mon. Not. Roy. Astron. Soc. 263, 789. DOI. ADS. ADSCrossRefGoogle Scholar
  24. Raouafi, N.-E., Solanki, S.K.: 2004, Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona? Astron. Astrophys. 427, 725. DOI. ADS. ADSCrossRefGoogle Scholar
  25. Sakurai, T.: 2017, Heating mechanisms of the solar corona. Proc. Japan Acad. Ser. B 93, 87. DOI. ADS. ADSCrossRefGoogle Scholar
  26. Singh, J., Sakurai, T., Ichimoto, K., Muneer, S.: 2006, Spectroscopic studies of solar corona VI: Trend in line-width variation of coronal emission lines with height independent of the structure of coronal loops. J. Astrophys. Astron. 27, 115. DOI. ADS. ADSCrossRefGoogle Scholar
  27. Teriaca, L., Banerjee, D., Doyle, J.G., Erdély, R.: 1999, SUMER observations of line shifts in the quiet sun and in an active region. In: Vial, J.-C., Kaldeich-Schü, B. (eds.) 8th SOHO Workshop: Plasma Dynamics and Diagnostics in the Solar Transition Region and Corona, ESA Special Publication 446, 645. ADS. Google Scholar

Copyright information

© Springer Nature B.V. 2019

Authors and Affiliations

  1. 1.Indian Institute of AstrophysicsBangaloreIndia
  2. 2.Physical Research LaboratoryAhmedabadIndia

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