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Magnetic Energy Spectrum and Intermittency in Active Regions
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Magnetic Energy Spectrum and Intermittency in Active Regions

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  1. Magnetic Energy Spectrum and Intermittency in Active Regions Valentina Abramenko andVasyl Yurchyshyn Big Bear Solar Observetory www.bbso.njit.edu/~avi/ AAS SPD 216th meeting: Miami, FL, May 27, 2010

  2. Photosphere: highly developed turbulence • Inherently non-linear nature of turbulence • A spectrum of values representing the behavior of the magnetic field at different scales • should be invoked • Magnetic Energy Spectrum • Intermittency Spectrum AAS SPD 216th meeting: Miami, FL, May 27, 2010

  3. Magnetic Energy Spectrum: Abramenko, ApJ 629, 2005 : 15 ARs Comparison with Flare Productivity AAS SPD 216th meeting: Miami, FL, May 27, 2010

  4. K41 α= Data • We analyzed 214 ARs observed during Jan, 1997 – Dec, 2006; • SOHO/MDI high resolution mode; • AR of non-zero flare index, A, and of Unsigned Flux>1022 Mx AAS SPD 216th meeting: Miami, FL, May 27, 2010

  5. Magnetic Energy Spectrum vs. Flare Index K41 X M C Green- unipolar sunspots; Red – emerging ARs; Blue – decaying ARs; Black – well-developed stable ARs AAS SPD 216th meeting: Miami, FL, May 27, 2010

  6. Intermittency Spectrum: What “Internittency” means? Intermittent (multi-fractal) process Non-intermittent Gaussian process Intermittency Spectra

  7. Intermittency Spectra for different ARs AAS SPD 216th meeting: Miami, FL, May 27, 2010

  8. Flatness Exponent vs. Flare Index Red – emerging ARs; Blue – decaying ARs; Black – well-developed stable ARs; Green- unipolar sunspots. AAS SPD 216th meeting: Miami, FL, May 27, 2010

  9. Intermittency spectra in Different Directions AAS SPD 216th meeting: Miami, FL, May 27, 2010

  10. Outcomes • Magnetic energy spectra of ARs display a well-defined power-law interval, which • indicates a presence of a turbulent non-linear energy cascade. • The power index well correlates with the flare productivity index. • Intermittency at small scales is relevant to flare productivity. The intermittency • spectra are much steeper for ARs of hither flare productivity. The small-scale • intermittency is present in all ARs except unipolar sunspots. • In flare-productive ARs, angular variations of intermittency are highly inhomo- • geneous. Small-scale shredded and stressed magnetic filaments are responsible • for formation of small-scale intermittency and they are relevant to the high flare • rate. AAS SPD 216th meeting: Miami, FL, May 27, 2010

  11. Intermittency Spectrum Structure functions Abramenko et al.2002 Flatness function AAS SPD 216th meeting: Miami, FL, May 27, 2010

  12. AAS SPD 216th meeting: Miami, FL, May 27, 2010

  13. AAS SPD 216th meeting: Miami, FL, May 27, 2010