Solar cycle variation of p-mode frequencies

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Solar cycle variationof p-mode frequencies

• Hiromoto Shibahashi
• (University of Tokyo)
• The First Far Eastern Workshop on Helioseismology
• March 15-17, 2003
• Korea Institute for Advanced Study

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Long-term frequency variation

• Dependent on mode frequency
• Very weak l-dependence
• Sudden drop near the acoustic cut-off frequency
• High degree l mode analyses

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Long-term frequency variation
??
High degree l p-modes
?
?crit
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Wave equation
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?crit
l(l1)1/2c/r
?c(r)
rsource
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Basic idea

• Variation in ?c(r) ??(?)
• Variation in c(r) ??(?/l)
• Variation of source layer
• ??(?) for ?gt?crit

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Quantization condition
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Long-term variation for fixed n
??
?
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Once ?c(r) determined, ?rs can be determined.
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Summary

• Variation of acoustic potential
• Frequency dependence part
• Frequency / Degree dependence part
• Variation of source layer
• Variation in HIP frequency
• Magnetic variation
• Irradiance variation