In the run up to April’s total solar eclipse, ESA-led Solar Orbiter and NASA-led Parker Solar Probe...
In the run up to April's total solar eclipse, ESA-led Solar Orbiter and NASA-led Parker Solar Probe are both at their closest approach to the Sun.
"On this day, we have a unique spacecraft configuration, where Solar Orbiter will have its full suite of instruments pointed towards the region on the Sun where the solar wind is produced that will hit Parker Solar Probe a few hours later."
The simultaneous close approach by Parker Solar Probe means that only a few hours after the source regions of the solar wind have been imaged by Solar Orbiter, the plasma of this nearly pristine solar wind be sampled in space by Parker Solar Probe.
Wait at its closest approach, Solar Orbiter is 45 million km from the Sun, whilst Parker Solar Probe is just 7.3 million km away.
So how does Solar Orbiter observe something that later hits Parker Solar Probe?
In this case, Parker Solar Probe will measure solar wind particles that travel away from the Sun at speeds of more than a million kilometres per hour.
"However, Parker Solar Probe comes much closer to the Sun, so can directly measure the properties of the solar wind - like its density and temperature - closer to its birthplace, before these properties change on its journey away from the Sun.".
"We will really hit the jackpot if Solar Orbiter observes a coronal mass ejection heading towards Parker Solar Probe," adds Andrei.
Parker Solar Probe's instruments are designed to sample the Sun's corona, targeting the region of space where the coronal plasma detaches to become the solar wind.
Beyond accomplishing its own science goals, Solar Orbiter will provide contextual information to improve the understanding of Parker Solar Probe's in situ measurements.