Bauer, S. J.Hartle, R. E.Herman, Jay2023-07-062023-07-061970-02-07Bauer, S., Hartle, R. & Herman, J. Topside Ionosphere of Venus and its Interaction with the Solar Wind. Nature 225, 533–534 (1970). https://doi.org/10.1038/225533a0https://doi.org/10.1038/225533a0http://hdl.handle.net/11603/28421THE abrupt termination of the daytime ionosphere of Venus at about 500 km observed with the Mariner V two-frequency occultation experiment provides an extremely interesting picture of the direct interaction of the solar wind with a planetary ionosphere1,2. It has been suggested that a pseudo-magnetopause is formed by magnetic fields carried along by the solar wind and forced to pile up on the topside of the highly conducting planetary ionosphere3,4. This magnetic obstacle then interacts with the superalfvénic and supersonic solar wind to form a bow shock; evidence for such a bow shock has been obtained by experiments on Mariner V and Venera IV (refs. 2 and 5).2 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domain Mark 1.0http://creativecommons.org/publicdomain/mark/1.0/Text