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Magnetography of Solar Flaring Loops with Microwave Imaging Spectropolarimetry

  • D. E. Gary
  • G. D. Fleishman
  • G. M. Nita

Abstract

We have developed a general framework for modeling gyrosynchrotron and free–free emission from solar flaring loops and used it to test the premise that 2D maps of source parameters, particularly the magnetic field, can be deduced from spatially resolved microwave spectropolarimetry data. We show quantitative results for a flaring loop with a realistic magnetic geometry, derived from a magnetic-field extrapolation, and containing an electron distribution with typical thermal and nonthermal parameters, after folding through the instrumental profile of a realistic interferometric array. We compare the parameters generated from forward-fitting a homogeneous source model to each line of sight through the folded image data cube both with the original parameters used in the model and with parameters generated from forward-fitting a homogeneous source model to the original (unfolded) image data cube. We find excellent agreement in general, but with systematic effects that can be understood as due to the finite resolution in the folded images and the variation of parameters along the line of sight, which are ignored in the homogeneous source model. We discuss the use of such 2D parameter maps within a larger framework of 3D modeling, and the prospects for applying these methods to data from a new generation of multifrequency radio arrays now or soon to be available.

Keywords

Solar Phys Solar Corona Imaging Spectroscopy Data Cube Microwave Emission 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Altyntsev, A.T., Fleishman, G.D., Huang, G.-L., Melnikov, V.F.: 2008, A broadband microwave burst produced by electron beams. Astrophys. J. 677, 1367 – 1377. doi: 10.1086/528841. ADSCrossRefGoogle Scholar
  2. Aschwanden, M.J.: 2008, Keynote address: outstanding problems in solar physics. J. Astrophys. Astron. 29, 3 – 16. doi: 10.1007/s12036-008-0002-5. ADSCrossRefGoogle Scholar
  3. Bastian, T.S.: 1995, Angular scattering of radio waves: implications for mode coupling in the solar corona. Astrophys. J. 439, 494 – 498. doi: 10.1086/175190. ADSCrossRefGoogle Scholar
  4. Bastian, T.S.: 2006, Magnetic field measurements in flare loops and CMEs. In: Casini, R., Lites, B.W. (eds.) Solar Polarization 4 CS-358, Astron. Soc. Pac., San Francisco, 173. Google Scholar
  5. Bastian, T.S., Benz, A.O., Gary, D.E.: 1998, Radio emission from solar flares. Annu. Rev. Astron. Astrophys. 36, 131 – 188. doi: 10.1146/annurev.astro.36.1.131. ADSCrossRefGoogle Scholar
  6. Bastian, T.S., Fleishman, G.D., Gary, D.E.: 2007, Radio spectral evolution of an X-ray-poor impulsive solar flare: implications for plasma heating and electron acceleration. Astrophys. J. 666, 1256 – 1267. doi: 10.1086/520106. ADSCrossRefGoogle Scholar
  7. Conway, J.E., Cornwell, T.J., Wilkinson, P.N.: 1990, Multi-frequency synthesis – a new technique in radio interferometric imaging. Mon. Not. Roy. Astron. Soc. 246, 490. ADSGoogle Scholar
  8. De Rosa, M.L., Schrijver, C.J., Barnes, G., Leka, K.D., Lites, B.W., Aschwanden, M.J., Amari, T., Canou, A., McTiernan, J.M., Régnier, S., Thalmann, J.K., Valori, G., Wheatland, M.S., Wiegelmann, T., Cheung, M.C.M., Conlon, P.A., Fuhrmann, M., Inhester, B., Tadesse, T.: 2009, A critical assessment of nonlinear force-free field modeling of the solar corona for active region 10953. Astrophys. J. 696, 1780 – 1791. doi: 10.1088/0004-637X/696/2/1780. ADSCrossRefGoogle Scholar
  9. Fleishman, G.D., Kuznetsov, A.A.: 2010, Fast gyrosynchrotron codes. Astrophys. J. 721, 1127 – 1141. doi: 10.1088/0004-637X/721/2/1127. ADSCrossRefGoogle Scholar
  10. Fleishman, G.D., Nita, G.M., Gary, D.E.: 2009, Dynamic magnetography of solar flaring loops. Astrophys. J. Lett. 698, L183 – L187. doi: 10.1088/0004-637X/698/2/L183. ADSCrossRefGoogle Scholar
  11. Fleishman, G., Gary, D., Nita, G., Alexander, D., Aschwanden, M., Bastian, T., Hudson, H., Hurford, G., Kontar, E., Longcope, D., Mikic, Z., DeRosa, M., Ryan, J., White, S.: 2010, Uncovering mechanisms of coronal magnetism via advanced 3D modeling of flares and active regions. arXiv:1011.2800.
  12. Fleishman, G.D., Kontar, E.P., Nita, G.M., Gary, D.E.: 2011, A cold, tenuous solar flare: acceleration without heating. Astrophys. J. Lett. 731, L19. doi: 10.1088/2041-8205/731/1/L19. ADSCrossRefGoogle Scholar
  13. Fleishman, G.D., Kontar, E.P., Nita, G.M., Gary, D.E.: 2013, Probing dynamics of electron acceleration with radio and X-ray spectroscopy, imaging, and timing in the 2002 April 11 solar flare. Astrophys. J. 768, 1. doi: 10.1088/0004-637X/768/1/1. arXiv:1303.4098. CrossRefGoogle Scholar
  14. Gary, D.E., Keller, C.U. (eds.): 2004, Solar and Space Weather Radiophysics – Current Status and Future Developments, Astrophys. Space Science Lib. 314, Kluwer Academic. Dordrecht. Google Scholar
  15. Gary, D.E., Hurford, G.J., Nita, G.M., White, S.M., Tun, S.D., Fleishman, G.D., McTiernan, J.M.: 2011, The expanded Owens Valley solar array. Bull. Am. Astron. Soc. 42, 102. Google Scholar
  16. Lin, H., Kuhn, J.R., Coulter, R.: 2004, Coronal magnetic field measurements. Astrophys. J. Lett. 613, L177 – L180. doi: 10.1086/425217. ADSCrossRefGoogle Scholar
  17. Lin, H., Penn, M.J., Tomczyk, S.: 2000, A new precise measurement of the coronal magnetic field strength. Astrophys. J. Lett. 541, L83 – L86. doi: 10.1086/312900. ADSCrossRefGoogle Scholar
  18. Liu, Y., Lin, H.: 2008, Observational test of coronal magnetic field models. I. Comparison with potential field model. Astrophys. J. 680, 1496 – 1507. doi: 10.1086/588645. ADSCrossRefGoogle Scholar
  19. Metcalf, T.R., Leka, K.D., Barnes, G., Lites, B.W., Georgoulis, M.K., Pevtsov, A.A., Balasubramaniam, K.S., Gary, G.A., Jing, J., Li, J., Liu, Y., Wang, H.N., Abramenko, V., Yurchyshyn, V., Moon, Y.-J.: 2006, An overview of existing algorithms for resolving the 180 ambiguity in vector magnetic fields: quantitative tests with synthetic data. Solar Phys. 237, 267 – 296. doi: 10.1007/s11207-006-0170-x. ADSCrossRefGoogle Scholar
  20. Mok, Y., Mikić, Z., Lionello, R., Linker, J.A.: 2008, The formation of coronal loops by thermal instability in three dimensions. Astrophys. J. Lett. 679, L161 – L165. doi: 10.1086/589440. ADSCrossRefGoogle Scholar
  21. Nita, G.M., Fleishman, G.D., Gary, D.E., Kuznetsov, A., Kontar, E.P.: 2011, GX_Simulator: an interactive IDL widget tool for visualization and simulation of imaging spectroscopy. Bull. Am. Astron. Soc. 42, 1811. Google Scholar
  22. Nita, G.M., Fleishman, G.D., Gary, D.E., Kuznetsov, A., Kontar, E.P.: 2012, Integrated IDL tool for 3D modeling and imaging data analysis. Bull. Am. Astron. Soc. 220, 51. Google Scholar
  23. Press, W.H., Flannery, B.P., Teukolsky, S.A.: 1986, Numerical Recipes. The Art of Scientific Computing, Cambridge University Press, Cambridge. MATHGoogle Scholar
  24. Rau, U., Cornwell, T.J.: 2011, A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometry. Astron. Astrophys. 532, A71. doi: 10.1051/0004-6361/201117104. ADSCrossRefGoogle Scholar
  25. Sault, R.J., Wieringa, M.H.: 1994, Multi-frequency synthesis techniques in radio interferometric imaging. Astron. Astrophys. Suppl. Ser. 108, 585 – 594. ADSGoogle Scholar
  26. Sault, R.J., Teuben, P.J., Wright, M.C.H.: 2011, MIRIAD: multi-channel image reconstruction, image analysis, and display. In: Astrophysics Source Code Library, 6007, ascl.net/1106.007. Google Scholar
  27. Socas-Navarro, H., Elmore, D., Pietarila, A., Darnell, A., Lites, B.W., Tomczyk, S., Hegwer, S.: 2006, Spinor: visible and infrared spectro-polarimetry at the National Solar Observatory. Solar Phys. 235, 55 – 73. doi: 10.1007/s11207-006-0020-x. ADSCrossRefGoogle Scholar
  28. Tomczyk, S.: 2012, The Coronal Solar Magnetism Observatory (COSMO). Am. Astron. Soc. Meet. 220, #202.11. ADS:2012AAS...22020211T. ADSGoogle Scholar
  29. White, S.M., Thejappa, G., Kundu, M.R.: 1992, Observations of mode coupling in the solar corona and bipolar noise storms. Solar Phys. 138, 163 – 187. doi: 10.1007/BF00146202. ADSCrossRefGoogle Scholar
  30. Wiegelmann, T., Inhester, B., Sakurai, T.: 2006, Preprocessing of Vector Magnetograph data for a nonlinear force-free magnetic field reconstruction. Solar Phys. 233, 215 – 232. doi: 10.1007/s11207-006-2092-z. ADSCrossRefGoogle Scholar
  31. Wiegelmann, T., Thalmann, J.K., Schrijver, C.J., De Rosa, M.L., Metcalf, T.R.: 2008, Can we improve the preprocessing of photospheric vector magnetograms by the inclusion of chromospheric observations? Solar Phys. 247, 249 – 267. doi: 10.1007/s11207-008-9130-y. ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.Physics Dept.New Jersey Institute of TechnologyNewarkUSA

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