Review: Recent Observations on Wave Heating

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Review Recent Observations on Wave Heating

• S. Kamio
• Kwasan and Hida Observatories
• Kyoto University

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Observing wave

• IntensityDensity fluctuationApparent motion of
  coronal structure
• Doppler velocityBulk motion of plasma
• Line width variationUnresolved motion
  (non-thermal)

Because corona is optically thin, observation is
effected by line of sight integration.
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Loop Oscillation

• Loop oscillation observed in M4.6 flare (TRACE
  171Å)
• Oscillation period at the loop top 27625s

Aschwanden, M. J. et al. 1999, ApJ, 520, 880.
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Wave mode

• Observed period 5min
• AssumptionL130,000kmne109 cm-3B20G?fast
  kink mode

Aschwanden, M. J. et al. 1999, ApJ, 520, 880.
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Visible Light

• Coronagraph at Lomnicky Stit and Norikura
• Fe XIV 5303Å (Green line, T2MK) and continuum
• Temporal variation for 2 hours

White light pB map, contrast enhanced
Minarovjech, M. et al. 2003, SoPh, 213, 269.
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Wavelet Analysis

• Line intensitypeak in 220-320s
• Continuumpeak in 500-950s
• Doppler velocitypeaks at 300s and 700s

Minarovjech, M. et al. 2003, SoPh, 213, 269.
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SOHO Spectrometers

• SUMER(Solar Ultraviolet Measurements of Emitted
  Radiation) UV Spectrometer (660-1610Å)
• CDS(Coronal Diagnostic Spectrometer)NIS(308-381Å,
  513-633Å), GIS(151-785Å)
• UVCS(Ultraviolet Coronagraph Spectrometer)Lya(121
  6Å), O IV(1037Å), WL(Linear Polarization)Observat
  ion range 1 - 12R?

Observe temporal and spatial variations ofLine
width, Doppler velocity, and Intensity.
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Polar Plumes

• SOHO/CDSNo scanning modeO V 629Å (logTe5.4)
  Intensity and velocity variations in 1 hour

• Plumes are denser and cooler plasma, where high
  speed solar wind is generated.
• CDS Slit covers polar coronal hole and plume

Banerjee, D. et al. 2000, SoPh, 196, 63.
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Wavelet Analysis

• Strong Power 1.65mHz(P10min)
• Intermittent nature Coherence time of 30min
• Intensity oscillation is caused by slow
  magneto-acoustic wave

Banerjee, D. et al. 2000, SoPh, 196, 63.
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Density Fluctuation

• SOHO/UVCSWLC (polarimeter)pB value related to
  electron density
• Strong power near1.6-1.8mHz (10min)

• Density fluctuation appear intermittently with
  coherence time of 30 min

Ofman, L. et al. 2000, ApJ, 529, 592.
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Group Speed

• Time lag between 1.9 and 2.1R?656165s
• Assuming solar speed is 9020 km/s, wave speed is
  12058km/s

Comparable to the sound speed in 106K corona
Ofman, L. et al. 2000, ApJ, 529, 592.
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Equatorial Corona

• SOHO/CDSOff limb observation of quiet coronaO V
  and Mg X
• Line width variationup to the height of 140,000km

Non-thermal
Instrumental
Harrison, R.A. et al. 2002, AA, 392, 319.
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Line Narrowing

• Line width decreased by 10 above 50,000km
• Amplitude of wave must increase in decreasing
  dentisy.
• ? Line narrowing suggests wave dissipation

limb
Harrison, R.A. et al. 2002, AA, 392, 319.
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Polar Coronal Hole

• SOHO/SUMER(Si VIII Te8x105K), UVCS, and LASCO
• Electron density distribution up to8R?
• Ne?r-2 above 4R?

Doyle, J.G. et al. 1999, AA, 349, 956.
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Line Broadening

• Sharp increase above 1.5R?
• Line width thermal (2kTi/M)1/2 non-thermal
• Ti 1.6 x 106K

Doyle, J.G. et al. 1999, AA, 349, 956.
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Non-thermal Velocity

• Theoretical relation of undamped propagating
  Alfven wave(Hollweg 1990)

Good agreement with the observation below 1.2R?
Doyle, J.G. et al. 1999, AA, 349, 956.
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Summary

• Previous papersCoronal wave and signature of
  dissipation have been found.
• Improved spectral resolution of Solar-B/EIS will
  enable us to study the corona in detail.
• Connection between chromosphere and
  coronaSpectroscopy of chromospheric lines with
  ground based stations and Solar-B/SOT

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Call for Papers
6-9 September 2004University of St Andrews, UK

• For more information, visithttp//www.soho15.org/

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