Spacecraft wakes in the solar wind

TL;DR

This paper investigates the properties of spacecraft wakes in the solar wind using data from the Cluster satellites, providing statistical analysis and methods to identify and remove wake signatures from electric field measurements.

Contribution

It offers new insights into the structure of spacecraft wakes in the solar wind and introduces a method to eliminate wake effects from electric field data.

Findings

Wake signatures appear as pulses of a few tenths of a volt in the data.

Statistical analysis of wake signatures correlates with solar wind parameters.

A method to remove wake signatures from electric field measurements is demonstrated.

Abstract

The solar wind flow creates a wake behind any spacecraft immersed in it. We study the properties of this wake using the spherical electrostatic probes of the Electric Fields and Waves (EFW) instruments on the Cluster satellites. The satellites spin in a plane inclined only a few degrees with respect to the ecliptic plane. The solar wind is often close to this plane, so each probe (44 m away from the spin axis) passes through the wake once every spin period (around 4 s), thereby sampling a cut of the wake electrostatic potential structure. The signature of the wake is clearly seen in the data as a pulse with an amplitude typically of a few tenths of a volt. We present statistics of the wake signatures as well as detailed examples, compare to solar wind parameters, and show a method to remove the wake signature from the electric field measurements.