Freiburg 2008 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 4: The Sun and Heliosphere - Poster Session

EP 4.4: Poster

Montag, 3. März 2008, 17:30–19:00, Vorraum KGI-Aula

On the Cutoff Behavior of Solar Magnetic Flux Tube Waves — •Reiner Hammer¹, Zdzislaw E. Musielak², and Swati Routh² — ¹Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany — ²University of Texas at Arlington, U.S.A.

The solar (sub)photosphere generates various types of waves by convective flows and by oscillations. Many of these waves can travel upward and contribute to the heating of the upper atmosphere and to dynamical phenomena like spicules. The ubiquitous photospheric 5-min oscillations have recently been observed to cause various effects in the upper atmosphere. However, such waves cannot easily traverse the photosphere and chromosphere as vertically propagating compressive waves, because of cutoff restrictions. Therefore it has been suggested that they travel as longitudinal waves inside flux tubes that are inclined to the vertical. We argue that in such inclined tubes transverse waves, which have much lower cutoff restrictions, should also be excited. Moreover we show that linear torsional tube waves have no cutoff as long as the flux tubes are thin, which can well be assumed in the photosphere. As soon as the tubes widen in the chromosphere, however, long period torsional waves are reflected.