The Solar Wind Interaction with Non-Magnetic Bodies and the Role of Small-Scale Structures

  1. J. H. Waite Jr.,
  2. J. L. Burch and
  3. R. L. Moore
  1. T. E. Cravens

Published Online: 18 MAR 2013

DOI: 10.1029/GM054p0353

Solar System Plasma Physics

Solar System Plasma Physics

How to Cite

Cravens, T. E. (1989) The Solar Wind Interaction with Non-Magnetic Bodies and the Role of Small-Scale Structures, in Solar System Plasma Physics (eds J. H. Waite, J. L. Burch and R. L. Moore), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM054p0353

Author Information

  1. Space Physics Research Laboratory, Department of Atmospheric, Oceanic and Space Sciences, The University of Michigan, Ann Arbor, Michigan 48109-2143

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875900742

Online ISBN: 9781118664315



  • Space plasmas;
  • Sun;
  • Magnetosphere;
  • Astrophysics


The solar wind interacts directly with the ionospheres and/or neutral atmospheres of non-magnetic bodies in the solar system. The solar wind with its associated interplanetary magnetic field is usually excluded from the highly conducting ionosphere of Venus due to currents induced in the ionospheric plasma. These currents are largely confined to the narrow ionopause layer during conditions of relatively low solar wind dynamic pressure. The ionosphere remains free of large-scale magnetic fields in this case, except for small-scale structures called magnetic flux ropes which have been observed throughout most of the dayside ionosphere by the magnetometer on the Pioneer Venus Orbiter. The formation and evolution of these flux ropes and their role in the momentum and energy balance of the ionosphere are not yet understood. Other small-scale plasma/field structures have been observed in the nightside ionosphere of Venus. During periods of high solar wind dynamic pressure, currents flow throughout the dayside ionosphere which is then permeated by large-scale magnetic fields. The solar wind interaction with comets is characterized by the mass loading of the solar wind with heavy cometary ions which are produced by the ionization of neutrals in the extensive cometary coma. This mass loading slows down the solar wind and ultimately leads to the formation of a magnetic barrier and a magnetotail. The Giotto magnetometer has observed a diamagnetic cavity surrounding the nucleus, which is a consequence of an outward ionneutral drag force associated with the flow of cometary neutrals past plasma frozen onto field lines in the magnetic barrier. In addition to these large-scale structures, many small-scale plasma/field structures have been observed in comets including the bow shock, tail rays and kinks, and plasma pile-ups and depletions in the barrier. Theoretically, the existence of a very narrow layer of enhanced plasma density just inside the contact surface has been predicted. The role of these small-scale structures in the overall solar wind interaction scenario is not yet understood.