A Consolidated Grant Proposal for Solar and Planetary Science, 2022 - 2025 Project 8: Observing currents within giant planet ionospheres
Lead Research Organisation:
Northumbria University
Department Name: Fac of Engineering and Environment
Abstract
The past two decades have seen profound changes in our understanding of how aurorae are generated in giant planet atmospheres. Cassini and Juno's measurements of magnetic fields, in the auroral generation regions close to the planet and the far equatorial magnetospheric regions, have revealed complex and often beguiling currents that close into the planet's atmosphere. Highly dynamic images of the aurorae from the Hubble Space Telescope and these spacecraft provide a window into how these currents map into the surrounding space environment, giving us a detailed measure of the auroral flux produced by these currents, along with tantalising hints of their origin.
But, for all this wealth of information, the specific driving forces that power the auroral currents remains controversial. Unfortunately, these spacecraft have no way to measure how these currents close through the ionosphere - the region that is key to understanding how these currents are driven. We propose to utilise our extensive dataset of infrared telescope observations of the giant planets' ionospheres, already collected and reduced by the University of Leicester, to provide direct measurements of the auroral brightness and ion winds over an extended period. Using a proven observing technique that has already produced ground-breaking snapshots of the ionospheres of these planets, we will produce the first-ever long-term auroral current maps organized by local time and planetary phase, allowing a new depth of understanding on how gas giant aurorae are generated. In turn, this will provide vital evidence that will help us answer these key questions that remain unanswered following the Cassini and Juno space missions:
1. What drives Jupiter's main emission, and why is it so dependent upon local time?
2. What processes control Jupiter's polar aurora, and why do they switch off at night?
3. Does Saturn have weather-driven aurora, and does this cause its rotation rate to vary?
But, for all this wealth of information, the specific driving forces that power the auroral currents remains controversial. Unfortunately, these spacecraft have no way to measure how these currents close through the ionosphere - the region that is key to understanding how these currents are driven. We propose to utilise our extensive dataset of infrared telescope observations of the giant planets' ionospheres, already collected and reduced by the University of Leicester, to provide direct measurements of the auroral brightness and ion winds over an extended period. Using a proven observing technique that has already produced ground-breaking snapshots of the ionospheres of these planets, we will produce the first-ever long-term auroral current maps organized by local time and planetary phase, allowing a new depth of understanding on how gas giant aurorae are generated. In turn, this will provide vital evidence that will help us answer these key questions that remain unanswered following the Cassini and Juno space missions:
1. What drives Jupiter's main emission, and why is it so dependent upon local time?
2. What processes control Jupiter's polar aurora, and why do they switch off at night?
3. Does Saturn have weather-driven aurora, and does this cause its rotation rate to vary?
Organisations
People |
ORCID iD |
| Thomas Stallard (Principal Investigator) |