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Magnetic Dissipation in the Photosphere and Heating of the Corona

Magnetic Dissipation in the Photosphere and Heating of the Corona. Valentyna Abramenko Big Bear Solar Observatory and Alexei Pevtsov National Solar Observatory. Soft X-ray luminosity of the corona. Objects: Active regions near the center of the solar disk.

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Magnetic Dissipation in the Photosphere and Heating of the Corona

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  1. Magnetic Dissipation in the Photosphere and Heating of the Corona Valentyna Abramenko Big Bear Solar Observatory and Alexei Pevtsov National Solar Observatory

  2. Soft X-ray luminosity of the corona

  3. Objects: Active regions near the center of the solar disk Objects: Active regions near the center of the solar disk ? CORONA PHOTOSPHERE Data: Yohkoh/SXT Data: Al 0.1 μm channel AlMgMn-sandwich channel Data: SOHO/MDI high resolution magnetograms • Analyzed Quantities: • Averaged (over an area) flux • in each channel • Temperature • Emission Measure • Analyzed Quantitiy: • Averaged (over an area) magnetic • energy dissipation rate

  4. Magnetic energy dissipation

  5. Structure of Magnetic Energy Dissipation Magnetic energy dissipation, ε/η Line-of-sight Magnetic Field, Bz

  6. Flux density (Al.1) Flux density (AlMgMn) Magnetic dissipation versus averaged flux in Al.1 and AlMgMn channels

  7. Magnetic dissipation versus temperature and emission measure

  8. η = (150 ÷ 300) km2/s If we accept the effective thickness of the photosphere h = 500 km, the energy flux F=∫ εَ dh for different ARs varies in the range of F = (1 ÷ 14)×106 erg cm-2 s-1 Energy Flux Estimation Abramenko, Pevtsov, Romano,2006, ApJL 646

  9. Bz Bz Vh Poynting Flux vs X-ray Flux:area-averaged values Follow-up study: Tan, Jing, Abramenko, Pevtsov, Song, Park, Haimin Wang, 2007 ApJ, accepted Poynting Flux ~ Bh Bz Vh

  10. Poynting Flux vs X-ray Flux:area-integrated values Follow-up study: Tan, Jing, Abramenko, Pevtsov, Song, Park, Haimin Wang, 2007 ApJ, accepted

  11. Conclusions • Energy input due to the random motions strongly correlates with brightness, temperature and emission measure of the corona. • Energy flux is (1 ÷ 14)×106 erg cm-2 s-1, which is quite sufficient to heat the corona above ARs. • Magnetic diffusivity in ARs is (150 ÷ 300) km2/s, which is twice lower than in QS areas.

  12. Index of the magnetic power spectrum

  13. Index of the magnetic power spectrum versus averaged flux in Al.1 and AlMgMn channels

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