Plasma and Fusion Research

Volume 8, 2501105 (2013)

Overview Articles

Evaluation of Spectroscopic Modeling for Iron Ions and Study on Non-Equilibrium Ionization Phenomena for Solar and LHD Plasmas

Tetsuya WATANABE, Hirohisa HARA, Norimasa YAMAMOTO¹⁾, Daiji KATO²⁾, Hiroyuki A. SAKAUE²⁾ and Izumi MURAKAMI²⁾

: National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
1): Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 Japan
2): National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan

(Received 19 November 2012 / Accepted 13 May 2013 / Published 15 August 2013)

Abstract

Spectroscopic observations of EUV emission lines in the transition region (TR) and the corona provide unique information on physical conditions in the outer atmosphere of the Sun. The EUV Imaging Spectrometer (EIS) on board the Hinode satellite is capable of observing, for the first time in EUV, spectra and monochromatic images of plasmas in the solar TR and corona; these plasmas could possibly be in non-ionization-equilibrium conditions. EIS observes over two-wavelength bands of 170 - 210 Å and 250 - 290 Å, with typical time-resolutions of 1 - 10 seconds. Iron line emissions emerging from these wavelengths reveal that dynamic plasma accelerations and heating take place in the solar atmosphere. On the other hand, the tracer-encapsulated-pellet (TESPEL) experiments provide spectral information of EUV emission lines from iron ions produced in the Large Helical Device (LHD). Relatively cool plasmas with electron temperatures similar to those of the solar corona can be generated by controlling the neutral beam injector (NBI) system. A time-dependent collisional radiative (CR) model for elemental iron is developed as a common tool to diagnose temperatures and densities of those plasmas in the Sun and in LHD; no systematic model yet exists for iron ions in the L- and M-shell ionization stages, which are very important for coronal plasma diagnostics. Adopting the best available theoretical calculations, as well as generating the experimental data, we improve the atomic parameters of highly charged iron ions, and these results are used to extract more accurate diagnostic information out of the EIS spectra.

Keywords

EUV emission line, iron ion modeling, non-ionization equilibrium, solar corona, LHD TESPEL experiment

DOI: 10.1585/pfr.8.2501105

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References

[1] T. Watanabe, T. Kato, I. Murakami and N. Yamamoto, in AIP Conf. Proc. 901, 5th International Conference on Atomic and Molecular Data and Their Applications (ICAMDATA) (Melville: AIP) p.215 (2007).
[2] T. Watanabe and the EIS Team, Plasma Fusion Res. 2, S10011 (2007).
[3] C.M. Brown, U. Feldman, J.F. Seely and C.M. Korendyke, Astrophys. J. Suppl. 176, 511 (2008).
[4] E. Landi, G. Del Zanna, P.R. Young, K.P. Dere, H.E. Mason and M. Landini, Astrophys. J. Suppl. 162, 261 (2006).
[5] H. Hara, T. Watanabe, L.K. Harra, J.L. Culhane, P.R. Young, J.T. Mariska and G.A. Doschek, Astrophys. J. Lett. 678, L67 (2008).
[6] G.A. Doschek, H.P. Warren, J.T. Mariska, K. Muglach, J.L. Culhane, H. Hara and T. Watanabe, Astrophys. J. 686, 1362 (2008).
[7] B. De Pontieu, S.W. McIntosh, V.H. Hansteen and C.J. Schrijver, Astrophys. J. Lett. 701, L1 (2009).
[8] H. Hara, T. Watanabe, L.K. Harra, J.L. Culhane and P.R. Young, Astrophys. J. 741, 107 (2011).
[9] H.E. Petschek, in “The Physics of Solar Flares,” ed. W. N. Hess, NASA SP-50 (NASA, Washington, D.C.), 425 (1964).
[10] M.B. Chowdhuria, S. Morita, M. Goto, H. Nishimura, K. Nagai and S. Fujioka, Rev. Sci. Instrum. 78, 023501 (2007).
[11] A. Bar-Shalom, M. Klapisch and J. Oreg, J. Quant. Spectrose. Radiat. Transf. 71, 179 (2001).
[12] K.M. Aggarwal and F.P. Keenan, Astron. Astrophys. 418, 371 (2004).
[13] N. Yamamoto, T. Kato, H. Funaba, K Sato, N. Tamura, S. Sudo, P. Beiersdorfer and J.K. Lepson, Astrophys. J. 689, 646 (2008) [Y08].
[14] K.M. Aggarwal and F.P. Keenan, Astron. Astrophys. 429, 1117 (2005).
[15] F.P. Keenan, D.B. Jess, K.M. Aggarwal, J.W. Brosius and J.M. Davila, Mon. Not. R. Astron. Soc. 376, 205 (2007).
[16] T. Watanabe, H. Hara, N. Yamamoto, D. Kato, H.A. Sakaue, I. Murakami, T. Kato, N. Nakamura and P.R. Young, Astrophys. J. 692, 1294 (2009).
[17] I. Skobelev, I. Murakami and T. Kato, National Institute for Fusion Science Research Report, NIFS-DATA-95, 1 (2006).
[18] I. Skobelev, I. Murakami and T. Kato, National Institute for Fusion Science Research Report, NIFS-DATA-99, 1 (2007).
[19] H.P. Warren, U. Feldman and C.M. Brown, Astrophys. J. 685, 1277 (2008).
[20] G.A. Doschek, U. Feldman and A.K. Bhatia, Phys. Rev. A 43(5), 2565 (1991).
[21] G. Del Zanna and Y. Ishikawa, Astron. Astrophys. 508, 1517 (2009).
[22] P. Jönsson et al., National Institute for Fusion Science Research Report, NIFS-DATA-113, 1 (2011).
[23] H.A. Sakaue, N. Yamamoto, S. Morita, N. Nakamura, C. Chen, D. Kato, H. Kikuchi I. Murakami, S. Ohtani, H. Tanuma, T. Watanabe and H. Tawara, J. Appl. Phys. 109, 073304 (2011).
[24] Solar-C Working Group, “Interim Report on the Solar-C Mission Concept, Plan-B,” Chap. 3 (2011).
[25] S. Imada, I. Murakami, T. Watanabe, H. Hara and T. Shimizu, Astrophys. J. 742, 70 (2011).
[26] S. Imada, H. Hara, T. Watanabe, I. Murakami, L.K. Harra, T. Shimizu and E.G. Zweibel, Astrophys. J. 743, 57 (2011).

This paper may be cited as follows:

Tetsuya WATANABE, Hirohisa HARA, Norimasa YAMAMOTO, Daiji KATO, Hiroyuki A. SAKAUE and Izumi MURAKAMI, Plasma Fusion Res. 8, 2501105 (2013).