Lower Solar Chromosphere-Corona Transition Region. III. Implications of the Observed Quiet-Sun Emission Measure Including Wave Pressure Effects
Abstract
The observed form of the emission measure (EM) is used as a function of temperature to infer the wave energy flux density and pressure throughout the lower transition region (TR). This procedure eliminates the need for specifying how the wave energy flux density is damped and addresses the question of whether there is any form of the mechanical heating associated with the degradation of an upward traveling wave energy flux density which is consistent with the observed EM and other observational constraints for the quiet sun. It is found that the observed form of the EM curve is incompatible with waves traveling vertically at the sound speed, regardless of any filling factor arguments. The same conclusion also applies to waves traveling at the Alfven speed, unless it is assumed that the emission in lower TR lines originates solely from small, spatially unresolved regions of large magnetic field strength (100 G), which cover a small fraction (filling factors of 1 percent) of the solar surface.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1990
- DOI:
- 10.1086/168765
- Bibcode:
- 1990ApJ...355..309W
- Keywords:
-
- Chromosphere;
- Magnetohydrodynamic Waves;
- Solar Atmosphere;
- Solar Corona;
- Acoustic Velocity;
- Magnetic Flux;
- Radiative Transfer;
- Solar Activity Effects;
- Solar Physics;
- RADIATIVE TRANSFER;
- SUN: TRANSITION REGION;
- WAVE MOTIONS