Venus Tail Ray Observation near Earth

H. Grünwaldt, M. Neugebauer, M. Hilchenbach, P. Bochsler, D. Hovestadt, A. Bürgi, F. M. Ipavich, K.-U. Reiche, W. I. Axford, H. Balsiger, A. B. Galvin, J. Geiss, F. Gliem, G. Gloeckler, K. C. Hsieh, R. Kallenbach, B. Klecker, S. Livi, M. A. Lee, G. G. Managadze, E. Marsch, E. Möbius, M. Scholer, M. I. Verigin, B. Wilken, P. Wurz

Paper accepted for publication at GRL, April 1997.

In June, 1996, Venus passed through a very close inferior conjunction with the Sun. At that time the CTOF detector of the CELIAS mass spectrometer experiment on the SOHO spacecraft near Earth's L1 LaGrangian point was measuring heavy ions in the solar wind 4.5x107 km downstream of Venus. Close to the time predicted by simple geometric arguments for passage of SOHO through the Venus wake, CTOF made three encounters with unusual fluxes of O+ and C+ ions. Their energy distributions resembled those of tail rays originating in the Venus ionosphere or ionopause region rather than of ions produced in the corona of neutral atoms that surrounds the planet. The C+ abundance was appr. 10% of O+. The observed O+ speed was very close to the simultaneous solar wind speed and the O+ temperature was a cool 5600 K/amu. The flux densities for the three events were (2.4-4.4)x103 cm-2 s-1.

Return to the CELIAS publication page
Return to the CELIAS home page

Last Update: April 18, 1997, Peter Wurz