A Revised Understanding of the Structure of the Venusian Magnetotail From a High-Altitude Intercept With a Tail Ray by Parker Solar Probe

Abstract

One of the major discoveries of NASA's 1979–1991 Pioneer Venus Orbiter is that the nightside ionosphere becomes filamentary at high altitude, forming comet-like tail rays. Pioneer Venus Orbiter could not establish how much farther into the wake of Venus tail rays extend, nor understand how they form. Here we present plasma and fields data from the fourth flyby of Venus by NASA's Parker Solar Probe consistent with an intercept with an ionospheric tail ray. The observations unambiguously demonstrate that Venusian Ionotail Rays can extend to at least 7,800 km in altitude. Using the new Parker observations we are able to identify a tail ray encounter within the Venus Express dataset. We thus present a unified picture of the structure of the magnetotail of Venus based on combined Venus Express, Pioneer Venus Orbiter, and Parker observations, and recent hybrid modeling.