Flow instabilities of magnetic flux tubes

DOI10.1051/0004-6361:20077269zbMATH Open1211.85002arXiv0704.3685OpenAlexW4302488338WikidataQ68626407 ScholiaQ68626407MaRDI QIDQ5427174

Author name not available (Why is that?)

Publication date: 19 November 2007

Published in: (Search for Journal in Brave)

Abstract: Flow-induced instabilities are relevant for the storage and dynamics of magnetic fields in stellar convection zones and possibly also in other astrophysical contexts. We continue the study started in the first paper of this series by considering the stability properties of longitudinal flows along magnetic flux tubes. A linear stability analysis was carried out to determine criteria for the onset of instability in the framework of the approximation of thin magnetic flux tubes. In the non-dissipative case, we find Kelvin-Helmholtz instability for flow velocities exceeding a critical speed that depends on the Alfv{'e}n speed and on the ratio of the internal and external densities. Inclusion of a friction term proportional to the relative transverse velocity leads to a friction-driven instability connected with backward (or negative energy) waves. We discuss the physical nature of this instability. In the case of a stratified external medium, the Kelvin-Helmholtz instability and the friction-driven instability can set in for flow speeds significantly lower than the Alfv{'e}n speed. Dissipative effects can excite flow-driven instability below the thresholds for the Kelvin-Helmholtz and the undulatory (Parker-type) instabilities. This may be important for magnetic flux storage in stellar convection zones and for the stability of astrophysical jets.

Full work available at URL: https://arxiv.org/abs/0704.3685

Mathematics Subject Classification ID

No records found.

This page was built for publication: Flow instabilities of magnetic flux tubes

Report a bug (only for logged in users!)Click here to report a bug for this page (MaRDI item Q5427174)