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Review: Recent Observations on Wave Heating S. Kamio Kwasan and Hida Observatories Kyoto University
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Observing wave Intensity Density fluctuation Apparent motion of coronal structure Doppler velocity Bulk motion of plasma Line width variation Unresolved 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: 276±25s Aschwanden, M. J. et al. 1999, ApJ, 520, 880.
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Wave mode Observed period: 5min Assumption L=130,000km n e =10 9 cm -3 B=20G 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, T=2MK) and continuum Temporal variation for 2 hours Minarovjech, M. et al. 2003, SoPh, 213, 269. White light pB map, contrast enhanced
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Wavelet Analysis Line intensity peak in 220-320s Continuum peak in 500-950s Doppler velocity peaks 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) Lyα(1216Å), O IV(1037Å), WL(Linear Polarization) Observation range 1 - 12R Observe temporal and spatial variations of: Line width, Doppler velocity, and Intensity.
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Polar Plumes SOHO/CDS No scanning mode O V 629Å (logT e =5.4) Intensity and velocity variations in 1 hour Banerjee, D. et al. 2000, SoPh, 196, 63. Plumes are denser and cooler plasma, where high speed solar wind is generated. CDS Slit covers polar coronal hole and plume
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Wavelet Analysis Strong Power 1.65mHz(P=10min) Intermittent nature Coherence time of 30min Intensity oscillation is caused by slow magneto-acoustic wave Banerjee, D. et al. 2000, SoPh, 196, 63. FluctuationAlfvenAcoustic DensityNoYes VelocityYes
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Density Fluctuation SOHO/UVCS WLC (polarimeter) pB value: related to electron density Strong power near 1.6-1.8mHz (10min) Ofman, L. et al. 2000, ApJ, 529, 592. Density fluctuation appear intermittently with coherence time of 30 min
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Group Speed Time lag between 1.9 and 2.1R 656±165s Assuming solar speed is 90±20 km/s, wave speed is 120±58km/s Ofman, L. et al. 2000, ApJ, 529, 592. Comparable to the sound speed in 10 6 K corona
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Equatorial Corona SOHO/CDS Off limb observation of quiet corona O V and Mg X Line width variation up to the height of 140,000km Harrison, R.A. et al. 2002, A&A, 392, 319. Non-thermalInstrumental
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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 Harrison, R.A. et al. 2002, A&A, 392, 319. limb
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Polar Coronal Hole SOHO/SUMER(Si VIII T e =8x10 5 K), UVCS, and LASCO Electron density distribution up to 8R N e ∝ r -2 above 4R Doyle, J.G. et al. 1999, A&A, 349, 956.
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Line Broadening Sharp increase above 1.5R Line width : thermal (2kT i /M) 1/2 + non-thermal T i ~ 1.6 x 10 6 K Doyle, J.G. et al. 1999, A&A, 349, 956.
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Non-thermal Velocity Theoretical relation of undamped propagating Alfven wave(Hollweg 1990) Doyle, J.G. et al. 1999, A&A, 349, 956. Good agreement with the observation below 1.2R
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Summary Previous papers Coronal 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 corona: Spectroscopy of chromospheric lines with ground based stations and Solar-B/SOT
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Call for Papers For more information, visit http://www.soho15.org/ 6-9 September 2004 University of St Andrews, UK
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