Figure 5.

Sketch of the geometry and wave interaction in Pluto's wake. Locations are shown as projections on the x y plane of the Pluto Solar Heliographic (PSH) coordinate system, essentially looking down on Pluto's magnetosphere. The Sun direction is on the right. We show the location of New Horizons when observing the selected intensity peak and valley. Green = outline of the magnetic boundary of the wake; dotted lines = trajectories of the detected ions for the two considered look directions. Red and black curves are for two wave phases where the direction of the electric field is opposite. It can be seen that the electric field changes the trajectories of the ions. The electric field vector in the x y plane is shown as a blue line. Each arrowhead is for one of the wave phases shown here. Note that particularly the ions shown in red enter the wake from the side without ever being close to Pluto.