Advertisement

Solar Physics

, Volume 246, Issue 1, pp 145–164 | Cite as

Damped Oscillations of Coronal Loops

  • James Chen
  • Peter W. Schuck
Article
First Online:
Received:
Accepted:

Abstract

A mechanism of damped oscillations of a coronal loop is investigated. The loop is treated as a thin toroidal flux rope with two stationary photospheric footpoints, carrying both toroidal and poloidal currents. The forces and the flux-rope dynamics are described within the framework of ideal magnetohydrodynamics (MHD). The main features of the theory are the following: i) Oscillatory motions are determined by the Lorentz force that acts on curved current-carrying plasma structures and ii) damping is caused by drag that provides the momentum coupling between the flux rope and the ambient coronal plasma. The oscillation is restricted to the vertical plane of the flux rope. The initial equilibrium flux rope is set into oscillation by a pulse of upflow of the ambient plasma. The theory is applied to two events of oscillating loops observed by the Transition Region and Coronal Explorer (TRACE). It is shown that the Lorentz force and drag with a reasonable value of the coupling coefficient (c d ) and without anomalous dissipation are able to accurately account for the observed damped oscillations. The analysis shows that the variations in the observed intensity can be explained by the minor radial expansion and contraction. For the two events, the values of the drag coefficient consistent with the observed damping times are in the range c d ≈2 – 5, with specific values being dependent on parameters such as the loop density, ambient magnetic field, and the loop geometry. This range is consistent with a previous MHD simulation study and with values used to reproduce the observed trajectories of coronal mass ejections (CMEs).

Keywords

Sun: magnetic field Sun: corona Sun: coronal loops Sun: oscillations Sun: flux ropes 
This is a preview of subscription content, log in to check access.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Arregui, I., Andries, J., Van Doorsselaere, T., Goossens, M., Poedts, S.: 2007, Astron. Astrophys. 463, 333. CrossRefADSGoogle Scholar
  2. Aschwanden, M.J., Fletcher, L., Schrijver, C.J., Alexander, D.: 1999, Astrophys. J. 520, 880. CrossRefADSGoogle Scholar
  3. Aschwanden, M.J., De Pontieu, B., Schrijver, C.J., Title, A.: 2002, Solar Phys. 206, 99. CrossRefADSGoogle Scholar
  4. Aschwanden, M.J., Nightingale, R.W., Andries, J., Goossens, M., Van Doorsselaere, T.: 2003, Astrophys. J. 598, 1375. CrossRefADSGoogle Scholar
  5. Brady, C.S., Arber, T.D.: 2005, Astron. Astrophys. 438, 733. CrossRefADSGoogle Scholar
  6. Brady, C.S., Verwichte, E., Arber, T.D.: 2006, Astron. Astrophys. 449, 389. CrossRefADSGoogle Scholar
  7. Cargill, P.J., Chen, J., Garren, D.A.: 1994, Astrophys. J. 423, 854. CrossRefADSGoogle Scholar
  8. Cargill, P.J., Chen, J., Spicer, D.S., Zalesak, S.T.: 1995, Geophys. Res. Lett. 22, 647. CrossRefADSGoogle Scholar
  9. Cargill, P.J., Chen, J., Spicer, D.S., Zalesak, S.T.: 1996, J. Geophys. Res. 101, 4855. CrossRefADSGoogle Scholar
  10. Chen, J.: 1989, Astrophys. J. 338, 453. CrossRefADSMathSciNetGoogle Scholar
  11. Chen, J.: 1990. In: Russell, C.T., Priest, E.R., Lee, L.C. (eds.) The Physics of Flux Ropes, Geophys. Monogr. Ser. 58, AGU, Washington, 269. Google Scholar
  12. Chen, J.: 1996, J. Geophys. Res. 101, 27499. CrossRefADSGoogle Scholar
  13. Chen, J., Garren, D.A.: 1993, Geophys. Res. Lett. 20, 2319. ADSGoogle Scholar
  14. Chen, J., Krall, J.: 2003, J. Geophys. Res. 108, A11. doi: 10.1029/2003JA009849. Google Scholar
  15. Chen, J., et al.: 1997, Astrophys. J. 490, L191. CrossRefADSGoogle Scholar
  16. Chen, J., et al.: 2000, Astrophys. J. 533, 481. CrossRefADSGoogle Scholar
  17. Garren, D.A., Chen, J.: 1994, Phys. Plasmas 1, 3425. CrossRefADSGoogle Scholar
  18. Gold, T., Hoyle, F.: 1960, Mon. Not. R. Astron. Soc. 120, 89. ADSGoogle Scholar
  19. Goossens, M., Ruderman, M.S., Hollweg, J.V.: 1995, Solar Phys. 157, 75. CrossRefADSGoogle Scholar
  20. Goossens, M., Andries, J., Aschwanden, M.J.: 2002, Astron. Astrophys. 394, L39. CrossRefADSGoogle Scholar
  21. Hyder, C.L.: 1966, Z. Astrophys. 63, 78. ADSGoogle Scholar
  22. Kadomtsev, B.B.: 1966. In: Reviews of Plasma Physics, 2, Consultants Bureau, New York, 153. Google Scholar
  23. Kleczek, J., Kuperus, M.: 1969, Solar Phys. 6, 72. CrossRefADSGoogle Scholar
  24. Krall, J., Chen, J.: 2005, Astrophys. J. 628, 1046. CrossRefADSGoogle Scholar
  25. Krall, J., Chen, J., Duffin, R.T., Howard, R.A., Thompson, B.J.: 2001, Astrophys. J. 562, 1045. CrossRefADSGoogle Scholar
  26. Nakariakov, V.M., Ofman, L.: 2001, Astron. Astrophys. 372, L53. CrossRefADSGoogle Scholar
  27. Nakariakov, V.M., Ofman, L., DeLuca, E.E., Roberts, B., Davila, J.M.: 1999, Science 285, 862. CrossRefADSGoogle Scholar
  28. Ofman, L., Davila, J.M., Steinolfson, R.S.: 1994, Astrophys. J. 421, 360. CrossRefADSGoogle Scholar
  29. Ramsey, H.E., Smith, S.F.: 1966, Astrophys. J. 71, 197. ADSGoogle Scholar
  30. Roberts, B.: 2000, Solar Phys. 193, 139. CrossRefADSGoogle Scholar
  31. Roberts, B., Edwin, P.M., Benz, A.O.: 1984, Astrophys. J. 279, 857. CrossRefADSGoogle Scholar
  32. Ruderman, M.S., Roberts, B.: 2002, Astrophys. J. 577, 475. CrossRefADSGoogle Scholar
  33. Schrijver, C.J., Brown, D.S.: 2000, Astrophys. J. 537, L69. CrossRefADSGoogle Scholar
  34. Schrijver, C.J., et al.: 1999, Solar Phys. 187, 261. CrossRefADSGoogle Scholar
  35. Seely, J.F., Feldman, U.: 1984, Astrophys. J. 280, L59. CrossRefADSGoogle Scholar
  36. Selwa, M., Solanki, S.K., Murawski, K., Wang, T.J., Shumlak, U.: 2006, Astron. Astrophys. 454, 653. CrossRefADSGoogle Scholar
  37. Shafranov, V.D.: 1966. In: Reviews of Plasma Physics, 2, Consultants Bureau, New York, 103. Google Scholar
  38. Terradas, J., Oliver, R., Ballester, J.L.: 2006, Astrophys. J. 650, L91. CrossRefADSGoogle Scholar
  39. Uralov, A.M.: 2003, Solar Phys. 218, 17. CrossRefADSGoogle Scholar
  40. Van Doorsselaere, T., Debosscher, A., Andries, J., Poedts, S.: 2004a, Astron. Astrophys. 424, 1065. CrossRefADSGoogle Scholar
  41. Van Doorsselaere, T., Andries, J., Poedts, S., Goossens, M.: 2004b, Astrophys. J. 606, 1223. CrossRefADSGoogle Scholar
  42. Verwichte, E., Foullon, C., Nakariakov, V.M.: 2006, Astron. Astrophys. 449, 769. CrossRefADSGoogle Scholar
  43. Vršnak, B., Ruždjak, V., Brajša, R., Zloch, F.: 1990, Solar Phys. 127, 119. CrossRefADSGoogle Scholar
  44. Wang, T.J., Solanki, S.K.: 2004, Astron. Astrophys. 421, L33. CrossRefADSGoogle Scholar
  45. Wood, B.E., Karovska, M., Chen, J., Brueckner, G.E., Cook, J.W., Howard, R.A.: 1999, Astrophys. J. 512, 484. CrossRefADSGoogle Scholar
  46. Xue, M.L., Chen, J.: 1983, Solar Phys. 84, 119. CrossRefADSGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  1. 1.Plasma Physics DivisionNaval Research LaboratoryWashingtonUSA

Personalised recommendations

Cite article

Buy options