eprintid: 1435
rev_number: 7
eprint_status: archive
userid: 1
dir: disk0/00/00/14/35
datestamp: 2001-02-26 13:55:00
lastmod: 2014-01-13 14:15:00
status_changed: 2012-08-14 15:01:12
type: doctoralThesis
metadata_visibility: show
creators_name: Gad El-Mawla, Diaa
title: Generation and propagation of longitudinal tube waves in late-type stellar atmospheres and the rotation-emission activity relation
title_de: Erzeugung und Ausbreitung longitudinaler Röhrenwellen in Atmosphären Später Sterne und die Rotations-Emissionsaktivitäts-Relation
ispublished: pub
subjects: 530
divisions: 714200
adv_faculty: af-13
keywords: FlußröhreStellar Atmosphere ,  magnetohydrodynamics , stellar rotation , radiative transfer , stellar chromospheres
cterms_swd: Sternatmosphäre
cterms_swd: Magnetohydrodynamik
cterms_swd: Sternrotation
cterms_swd: Chromosphäre
abstract_translated_text: Generated longitudinal tube wave (LTW) energy fluxes as a result of   the interaction of magnetic flux tubes with the turbulent medium of the  convection zones of late-type stars were computed. Solar magnetic flux tubes of different filling factors were heated with  adiabatic and radiatively damped LTW. It was found that the  tube geometry plays an important role for heating the outer layers. The response of the chromospheres of the Sun and two late-type stars  (of spectral types F5V & M0V) to the excitation by different wave modes  was studied. It was found that the magnetic atmosphere shows resonance oscillations  with longer periods in comparison with the non-magnetic plane parallel atmosphere.  Magnetic chromosphere models were constructed for late-type stars  based on our computed LTW fluxes.   The mean temperatures of all spectral types for a given magnetic filling  factor show a monotonic outward (classical) temperature rise.  A new picture of the heating of stellar chromospheres is presented. The  chromospheric emission can be explained by an ordered sequence of  different heating processes which systematically vary as a function  of height in the star and with its rotation rate.  The low chromosphere is heated by acoustic shock waves.  The middle and upper chromosphere by longitudinal and transverse  MHD waves via shock dissipation. For the highest chromosphere, wave  heating is insufficient and additional non-wave heating (e.g. magnetic reconnection)  is necessary. With increasing rotation, the magnetic heating mechanisms  become more important (rotation - emission activity relation).  Based on our computed Mg II fluxes we  estimate the rotational periods of G- and K- type-stars. 
abstract_translated_lang: eng
class_scheme: pacs
class_labels: 95.30.Q 97
date: 2001
date_type: published
id_scheme: DOI
id_number: 10.11588/heidok.00001435
portal_cluster_id: p-zah
portal_order: 01435
ppn_swb: 1643196413
own_urn: urn:nbn:de:bsz:16-heidok-14353
date_accepted: 2001-02-14
advisor: HASH(0x5561209f5808)
language: eng
bibsort: GADELMAWLAGENERATION2001
full_text_status: public
citation:   Gad El-Mawla, Diaa  (2001) Generation and propagation of longitudinal tube waves in late-type stellar atmospheres and the rotation-emission activity relation.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/1435/1/diss.pdf