Time-dependent Ionization in Solar and Stellar Magnetic Flux Tubes
Manfred Cuntz (Department of Physics, University of Texas at Arlington)
Wolfgang Rammacher (Institut fuer Theoretische Astrophysik, Univ. Heidelberg)
Peter Ulmschneider (Institut fuer Theoretische Astrophysik, Univ. Heidelberg)
We discuss the relevance of time-dependent ionization in solar / stellar magnetic flux tubes. We focus on detailed models of longitudinal tubes waves taking into account recent simulations of wave generation, propagation and dissipation available for the Sun and solar-type stars. In particular, we study tubes of different spreading as function of height representing tubes in environments of different magnetic filling factors. Time-dependent ionization is relevant in all models studied to date. The effects of time-dependent ionization are most pronounced in simulations of high-amplitude waves and in tubes
of narrow spreading owing to the properties of the waves
and the lack of dilution of the wave energy flux. This work is a further step toward future research that will also consider transverse and torsional waves, thus allowing a more thorough understanding of magnetic heating phenomena in solar and stellar chromospheres.
http://www.uta.edu/physics/cuntz.html