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Predicting observational signatures of coronal heating by Alfvén waves and nanoflares

Published online by Cambridge University Press:  01 September 2007

Patrick Antolin
Affiliation:
Kwasan Observatory, Kyoto University, Yamashina, Kyoto, 607-8471, Japan email: antolin@kwasan.kyoto-u.ac.jp, shibata@kwasan.kyoto-u.ac.jp
Kazunari Shibata
Affiliation:
Kwasan Observatory, Kyoto University, Yamashina, Kyoto, 607-8471, Japan email: antolin@kwasan.kyoto-u.ac.jp, shibata@kwasan.kyoto-u.ac.jp
Takahiro Kudoh
Affiliation:
National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588, Japan email: kudoh@th.nao.ac.jp, shiota@cfca.jp
Daiko Shiota
Affiliation:
National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588, Japan email: kudoh@th.nao.ac.jp, shiota@cfca.jp
David Brooks
Affiliation:
Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA email: dhbrooks@ssd5.nrl.navy.mil
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Abstract

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Alfvén waves can dissipate their energy by means of nonlinear mechanisms, and constitute good candidates to heat and maintain the solar corona to the observed few million degrees. Another appealing candidate is the nanoflare-reconnection heating, in which energy is released through many small magnetic reconnection events. Distinguishing the observational features of each mechanism is an extremely difficult task. On the other hand, observations have shown that energy release processes in the corona follow a power law distribution in frequency whose index may tell us whether small heating events contribute substantially to the heating or not. In this work we show a link between the power law index and the operating heating mechanism in a loop. We set up two coronal loop models: in the first model Alfvén waves created by footpoint shuffling nonlinearly convert to longitudinal modes which dissipate their energy through shocks; in the second model numerous heating events with nanoflare-like energies are input randomly along the loop, either distributed uniformly or concentrated at the footpoints. Both models are based on a 1.5-D MHD code. The obtained coronae differ in many aspects, for instance, in the simulated intensity profile that Hinode/XRT would observe. The intensity histograms display power law distributions whose indexes differ considerably. This number is found to be related to the distribution of the shocks along the loop. We thus test the observational signatures of the power law index as a diagnostic tool for the above heating mechanisms and the influence of the location of nanoflares.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

References

Anderson, C.S., & Athay, R.G. 1989, ApJ, 336, 1089CrossRefGoogle Scholar
Aschwanden, M.J. 2001, ApJ (Letters), 559, L171CrossRefGoogle Scholar
Aschwanden, M.J. 2004, Physics of the Solar Corona: An Introduction, Springer, BerlinGoogle Scholar
Alfvén, H. 1947, MNRAS, 107, 211CrossRefGoogle Scholar
Benz, A.O., & Krucker, S. 2002, ApJ, 568, 413CrossRefGoogle Scholar
Erdélyi, R. 2004, A&G, 45, 34Google Scholar
Erdélyi, R., & Ballai, I. 2007, AN, 328, 726Google Scholar
Evans, C.R., & Hawley, J.F. 1988, ApJ, 332, 659CrossRefGoogle Scholar
Hollweg, J.V., Jackson, S., & Galloway, D. 1982, Solar Phys., 75, 35CrossRefGoogle Scholar
Hori, K., Yokoyama, T., Kosugi, T., & Shibata, K. 1997, ApJ, 489, 426CrossRefGoogle Scholar
Hudson, H.S. 1991, Solar Phys., 133, 357CrossRefGoogle Scholar
James, S. P., & Erdélyi, R. 2002, A&A, 393, L11Google Scholar
Katsukawa, Y., & Tsuneta, S. 2001, ApJ, 557, 343CrossRefGoogle Scholar
Krucker, S., & Benz, A.O. 1998, ApJ (Letters), 501, L213CrossRefGoogle Scholar
Kudoh, T., Matsumoto, R., & Shibata, K. 1998, ApJ, 508, 186CrossRefGoogle Scholar
Kudoh, T., & Shibata, K. 1999, ApJ, 514, 493CrossRefGoogle Scholar
Mendoza-Briceño, C.A., Erdélyi, R., & Sigalotti, L.Di G. 2002, ApJ, 579, L49CrossRefGoogle Scholar
Mendoza-Briceño, C.A., Sigalotti, L.Di G., & Erdélyi, R. 2005, ApJ, 624, 1080CrossRefGoogle Scholar
Mendoza-Briceño, C.A., & Erdélyi, R. 2006, ApJ, 648, 722CrossRefGoogle Scholar
Moriyasu, S., Kudoh, T., Yokoyama, T., & Shibata, K. 2004, ApJ (Letters), 601, L107CrossRefGoogle Scholar
Parker, E.N. 1988, ApJ, 330, 474CrossRefGoogle Scholar
Parnell, C.E., & Jupp, P.E. 2000, ApJ, 529, 554CrossRefGoogle Scholar
Patsourakos, S., & Vial, J.-C. 2002, A&A 385, 1073Google Scholar
Priest, E.R., Foley, C.R., Heyvaerts, J., Arber, T.D., Culhane, J.L., & Acton, L.W. 1998, Nature, 393, 545CrossRefGoogle Scholar
Reale, F. 2002, ApJ, 580, 566CrossRefGoogle Scholar
Rosner, R., Tucker, W.H., & Vaiana, G.S. 1978, ApJ, 220, 643CrossRefGoogle Scholar
Shibata, K., Tajima, T., Matsumoto, R., Horiuchi, T., Hanawa, T., Rosner, R., & Uchida, Y. 1989a, ApJ, 338, 471CrossRefGoogle Scholar
Shibata, K., Tajima, T., Steinolfson, R.S., & Matsumoto, R. 1989b, ApJ, 345, 584CrossRefGoogle Scholar
Shimizu, T. 1995, PASJ, 47, 251Google Scholar
Stone, J.M., & Norman, M.L. 1992, ApJS, 80, 791CrossRefGoogle Scholar
Takeuchi, A., & Shibata, K. 2001, ApJ (Letters), 546, L73CrossRefGoogle Scholar
Taroyan, Y., Bradshaw, S.J., & Doyle, J.G. 2006, A&A, 446, 315Google Scholar
Taroyan, Y., Erdélyi, R., Doyle, J.G., & Bradshaw, S.J. 2007, A&A, 462, 331Google Scholar
Uchida, Y., & Kaburaki, O. 1974, Solar Phys., 35, 451CrossRefGoogle Scholar
Wentzel, D.G. 1974, Solar Phys., 39, 129CrossRefGoogle Scholar
Yabe, T., & Aoki, T. 1991, Comp. Phys. Comm., 66, 219CrossRefGoogle Scholar