Towfiq Ahmed

Magnetic Flux Tubes in Late-type Stars: Propagation and Generation of Transverse Waves in Magnetic Flux Tubes Towfiq Ahmed

One of the most important and still unsolved problems in stellar astrophysics is to identify the basic physical processes that are responsible for the extensive heating of the chromosphere and corona in late-type stellar atmospheres. Two widely accepted ways of heating are due to acoustic wave in non-magnetic region, and MHD (magneto- hydrodynamic) waves in the concentrated magnetic flux tube region. Out of three different MHD tube modes (transverse, longitudinal and torsional) this study only involves the propagation and generation of the transverse tube wave, which are the most efficient means of energy transfer in the stellar atmosphere. The current research has two components. First, starting from the general properties of magnetic flux tubes, propagation of stellar transverse tube waves and corresponding cutoff frequencies are determined analytically for the first time for non-isothermal stellar atmospheres. Second, the rate of transverse wave energy generation at the stellar surface at a given height has been calculated analytically for linear tube wave, and numerically for nonlinear tube wave in late-type stars for the first time.