MHD Waves on Solar Magnetic Flux Tubes Tutorial Review

  1. C. T. Russell,
  2. E. R. Priest and
  3. L. C. Lee
  1. Joseph V. Hollweg

Published Online: 21 MAR 2013

DOI: 10.1029/GM058p0023

Physics of Magnetic Flux Ropes

Physics of Magnetic Flux Ropes

How to Cite

Hollweg, J. V. (1990) MHD Waves on Solar Magnetic Flux Tubes Tutorial Review, in Physics of Magnetic Flux Ropes (eds C. T. Russell, E. R. Priest and L. C. Lee), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM058p0023

Author Information

  1. Physics Department and Institute for the Study of Earth, Oceans and Space, University of New Hampshire

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1990

ISBN Information

Print ISBN: 9780875900261

Online ISBN: 9781118663868

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Keywords:

  • Solar photosphere;
  • Magnetic flux;
  • Astrophysics

Summary

Solar magnetic flux tubes are intense (1000–2000G) fields at photospheric levels, concentrated into small (diameter ≈ few × 102 km) bundles. They are confined by the external gas pressure, but since this pressure decreases rapidly with height, the flux tubes fan out and lose their individual identities above some 500 km or so. This rapid variation with height makes realistic analysis of wave propagation very difficult, but in this tutorial we will review from a physical point of view some of the highly simplified models which have been studied. The torsional Alfvén mode is one case which can be investigated in detail, and we will discuss its propagation, reflection, and non-WKB properties. The thin flux tube approximation has been used at low heights, and we will discuss the sausage and kink modes described by it. In the corona one sees x-ray emitting loops, which are really plasma tubes in a roughly uniform magnetic field. Here much emphasis has been placed on surface waves and resonance absorption, which we will discuss in simple physical terms, with emphasis on its viability as a coronal heating mechanism. We will also discuss some recent work on resonant instabilities which can occur when bulk flows are present. Finally, we will discuss some nonlinear effects such as solitons, shock formation, and spicules.