AAS Meeting #194 - Chicago, Illinois, May/June 1999
Session 93. Quiet Photosphere, Chromosphere and Transition Region
Display, Thursday, June 3, 1999, 9:20am-4:00pm, Southeast Exhibit Hall

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[93.08] A Part-Time Solar Chromosphere?

W. Kalkofen (CfA)

The dynamical model of the nonmagnetic chromosphere of Carlsson & Stein (1994) has a time-dependent temperature structure from shock dissipation of upward-propagating acoustic waves. For the high-temperature phase of waves due to an observed photospheric velocity spectrum, the model reproduces to great fidelity the intricate velocity and intensity variations of the corresponding H line from an hour-long observing run. But for the low-temperature phase, in which the temperature drops monotonically in the outward direction up to a height of at least 1.8 Mm above \tau=1, the model predicts UV spectra for lines and continua that should be observable in absorption everywhere and almost all the time. However, observations with SUMER show only emission lines, everywhere and all the time.

The dynamical model fails as a temperature model because it uses less than 5% of the wave energy entering the chromosphere. The extra energy is hidden in the observed power spectrum at acoustic frequencies above 10 mHz; it accounts for a permanent temperature inversion and thus a full-time chromosphere.

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