Jupiter Mapping Model
Jupiter Mapping Model
Embedded Files
Welcome to the new online home for the Jupiter magnetosphere-ionosphere flux equivalence mapping model!
As of the MOP meeting in July 2024 the old website hosted by UCLA no longer works. IDL code that runs the mapping model is available via GitHub here. Please sign up using the form below to receive e-mail updates.
About the Vogt et al. (2011, 2015) flux equivalence mapping model
About the Vogt et al. (2011, 2015) flux equivalence mapping model
The Vogt et al. (2011, 2015) flux equivalence mapping model provides a way to link auroral features to their source regions in Jupiter's equatorial magnetosphere. It is based on the requirement that the flux through a given area in the ionosphere must equal the flux through the region to which it maps in the equator.
A flux equivalence approach is more accurate than tracing model field lines at distances in the middle to outer magnetosphere (beyond ~30 Jovian radii) because many field models are not well-constrained by data at large distances (for example, some do not account for local time asymmetries that are important at large distances).
Illustration of the flux equivalence mapping method. Field lines are traced from a model at Ganymede's orbit (green), where models can be verified by Ganymede's auroral footprint, but the ionosphere-magnetosphere link at larger distances is based on a flux calculation that accounts for 2-D (radial distance and local time) variations in the magnetic field.
Model output, code, and data files
Model output, code, and data files
IDL code that performs the mapping is available via GitHub at https://github.com/marissav06/jupiter-auroral-mapping. This IDL code takes either as its input a position in either the ionosphere or the equatorial magnetosphere and outputs the corresponding mapped position in the equatorial magnetosphere or ionosphere, respectively. The code does not actually run the flux equivalence calculation but calculates the mapping through interpolation using pre-calculated ionospheric mapping contours. (Please note that to run the IDL code you will need to download this zip file containing precalculated mapping contours in IDL .sav format.)
Text files containing ionospheric mapping contours output by the model, as well as figures showing the ionospheric mapping contours, are available here.
Recent and upcoming model updates
Recent and upcoming model updates
New field models: The original mapping model, published in 2011, used pre-Juno internal field models (VIP4 and the Grodent Anomaly Model) for tracing fieldlines to the 15 Rj (Ganymede) reference contour and calculate the ionospheric field. In 2015 we updated the flux eqivalence calculation to include the new VIPAL model, and in recent years we have updated it to include the Juno-era JRM09 and JRM33 internal field models in combination with the Con2020 magnetodisk model.
Including temporal variability (coming soon): Temporal variability in Jupiter's magnetosphere -- whether driven by internal or external processes -- affects the link between a point in the ionosphere and its mapped source region in the magnetosphere. We are in the process of updating the mapping model code to include temporal variability.
Translating the IDL code into Python (coming soon): We are working to translate the IDL code into Python so that the program can be run without the need for any expensive software licenses.
(Left) Measured changes in Jupiter's current sheet lead to shifts in the ionospheric footpaths of Io (5.9 Rj) and Ganymede (15 Rj) and will also impact the mapping of the main auroral oval near 30 Rj. (Right) Increases in the solar wind dynamic pressure compress Jupiter's magnetosphere, leading to an increased north-south component of the magnetic field (Bθ) in the magnetosphere. The figure at right shows how the increased Bθ shifts the ionospheric mapping contours calculated in the flux equivalence model -- the red (high solar wind dynamic pressure) contours are pushed poleward compared to the blue contours (low solar wind dynamic pressure).
Other figures and mapping results
Other figures and mapping results
The flux equivalence mapping model output predicts a region of open field lines (pink area labeled "polar cap" at right) that is nearly colocated with a region of high UV color ratio (middle) but is not strongly correlated with any UV brightness features (left) in Juno UVS observations. Modified from Bonfond et al. (2017).
The ionospheric contours output by the flux equivalence model can be used to determine the source region of various UV auroral features or regions. Above, ionospheric mapping contours are overlaid on auroral images from the Hubble Space Telescope. The model suggests that the auroral swirl region (red) is largely on open field lines and that the active region (green) is located at or near the dayside magnetopause, like a polar cusp (from Vogt et al. 2011).
Acknowledgments
This work is funded by NASA through the New Frontiers Data Analysis Program, grant 80NSSC24K0905.
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