AbstractWe have recently observed thirteen sunspots, both with CDS on SOHO and TRACE. For each sunspot we investigate the oscillations in the chromosphere, transition region and corona. Above the umbra the power spectra show one dominant peak corresponding to a period of 3 minutes. The intensity oscillation amplitude increases with increasing temperature, reaches a maximum for lines emitting close to 1–2 × 105 K, and decreases for higher temperatures. Part of the wave energy penetrates into the corona, channeled into small areas that appear to coincide with the endpoints of sunspot coronal loops. The observations support the hypothesis that the oscillations are caused by upwardly propagating acoustic waves and show no signs of the resonances, equally spaced ≈1 mHz in frequency, predicted by the chromospheric resonator theories.
Search for a chromospheric resonator above sunspots
Advances in Space Research ; 32 , 6 ; 1097-1102
2003-01-15
6 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Search for a chromospheric resonator above sunspots
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