“Wave” Analysis of Venus Ionospheric Flux Ropes

  1. C. T. Russell,
  2. E. R. Priest and
  3. L. C. Lee
  1. J. G. Luhmann

Published Online: 21 MAR 2013

DOI: 10.1029/GM058p0425

Physics of Magnetic Flux Ropes

Physics of Magnetic Flux Ropes

How to Cite

Luhmann, J. G. (1990) “Wave” Analysis of Venus Ionospheric Flux Ropes, 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/GM058p0425

Author Information

  1. Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90024

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

The details of the formation and evolution of filamentary magnetic structures observed in the Venus ionosphere by the Pioneer Venus Orbiter (PVO) remain subjects of debate. It is understood that magnetic flux from the overlying magnetosheath can be convected deep into the dayside ionosphere, but it is not known how this flux is intensified in localized regions or how the field is reoriented so that a nearly isotropic distribution of vectors is seen in the subsolar ionosphere. The initial analyses of these structures in terms of “flux rope” models concentrated on a special class which was designated the “small impact parameter” subset. However, the most frequently observed features do not fit into this (small impact parameter) category. To investigate the behavior of the general field fluctuations observed by the PVO magnetometer, wave analysis techniques were applied to study their compressional amplitude, ellipticity and sense of polarization. The most remarkable change in these properties occurs within ∼15° of the terminator. The ellipticity and compressional power drop markedly, implying that flux ropes either drastically change their character there or are simply confined to the dayside hemisphere within ∼750° of the subsolar point. A heuristic model which seeks to unify the interpretations of the dayside flux ropes and the “terminator waves” is suggested.