บทที่ 5 พลังงานแสงอาท ิตย · 2007-07-08 · 5.1.4.1 ชั้นโฟโตสเฟ ยร (photosphere) เป นชั้นบาง
Magnetic Dissipation in the Photosphere and Heating of the Corona
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Transcript of Magnetic Dissipation in the Photosphere and Heating of the Corona
Magnetic Dissipation in the Magnetic Dissipation in the Photosphere and Heating of Photosphere and Heating of
the Coronathe Corona
Valentyna AbramenkoValentyna AbramenkoBig Bear Solar ObservatoryBig Bear Solar Observatory
andandAlexei PevtsovAlexei Pevtsov
National Solar ObservatoryNational Solar Observatory
Soft X-ray luminosity of the Soft X-ray luminosity of the corona corona
Data: Yohkoh/SXT Data: Al 0.1 μm channel AlMgMn-sandwich channel
Data: SOHO/MDI high resolution magnetograms
Objects: Active regions near the center of the solar disk
Objects: Active regions near the center of the solar disk
Analyzed Quantities: •Averaged (over an area) flux in each channel•Temperature•Emission Measure
Analyzed Quantitiy: •Averaged (over an area)
magnetic energy dissipation rate
CORONACORONA PHOTOSPHEREPHOTOSPHERE
?
Magnetic energy dissipationMagnetic energy dissipation
Structure of Magnetic Energy Structure of Magnetic Energy DissipationDissipation
Line-of-sight Magnetic Field, BzMagnetic energy dissipation, ε/η
Magnetic dissipation versus averaged Magnetic dissipation versus averaged flux in Al.1 and AlMgMn channelsflux in Al.1 and AlMgMn channels
Flux d
ensi
ty (
Al.1
)
Flux d
ensi
ty (
AlM
gM
n)
Magnetic dissipation versus Magnetic dissipation versus temperature and emission temperature and emission
measuremeasure
Energy Flux EstimationEnergy Flux Estimation
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)×10F = (1 ÷ 14)×106 6 erg cmerg cm-2-2 s s-1-1
Abramenko, Pevtsov, Romano,2006, ApJL 646
Poynting Flux vs X-ray Flux:Poynting Flux vs X-ray Flux:area-averaged valuesarea-averaged values
Follow-up study: Tan, Jing, Abramenko, Pevtsov, Song, Park, Haimin Wang, 2007 ApJ, accepted
Poynting Flux ~ Bh Bz Vh
Bz Bz Vh
Poynting Flux vs X-ray Flux:Poynting Flux vs X-ray Flux:area-integrated valuesarea-integrated values
Follow-up study: Tan, Jing, Abramenko, Pevtsov, Song, Park, Haimin Wang,
2007 ApJ, accepted
•ConclusionsConclusions
Energy input due to the random motions Energy input due to the random motions strongly correlates with brightness, strongly correlates with brightness, temperature and emission measure of the temperature and emission measure of the corona.corona.
Energy flux is (1 ÷ 14)×10Energy flux is (1 ÷ 14)×1066 erg cm erg cm-2-2 s s-1-1, which , which is quite sufficient to heat the corona above is quite sufficient to heat the corona above ARs.ARs.
Magnetic diffusivity in ARs is Magnetic diffusivity in ARs is (150 ÷ 300) km2/s, which is twice lower than in QS areas., which is twice lower than in QS areas.
Index of the magnetic power spectrumIndex of the magnetic power spectrum
Index of the magnetic power spectrum Index of the magnetic power spectrum versus averaged flux in Al.1 and versus averaged flux in Al.1 and
AlMgMn channelsAlMgMn channels