Constrained by the initial, measured data, these outputs are representative of the actual, physical structures surrounding the auroral arc.
Once the data are prepared, GEMINI is run to generate several 3D, time-varying outputs, including the plasma currents and densities. Clayton and colleagues present two methods for accomplishing this and compare their relative performances. A key step in the process is converting these data, which cut across the model grid, into a 2D estimate of the plasma flow. In situ data are in the form of a 1D line of observed values corresponding to the flight path of the rocket. The study uses data from a 2017 sounding rocket launch. Credit: Jules van Irsel, Dartmouth Colleg The interconnections are shown between plasma density (in green), auroral currents (in red/blue), and plasma flows (orange/cyan). Data from the Isinglass rocket are used to guide the GEMINI computer model and derive 3D properties of the event. An Isinglass sounding rocket launch from Poker Flat, Alaska, gathered data to study an auroral arc. The particle data are derived from inversions of ground-based images, whereas the field data can be taken from in situ spacecraft observations or from ground-based radar. This model is driven with two distinct data sources: particle fluxes and electric field measurements. The new technique is built around the Geospace Environment Model of Ion-Neutral Interactions ( GEMINI), a 3D ionospheric model. The research team then demonstrated the approach’s ability to describe kilometer-scale plasma structures in the vicinity of an actual auroral arc.
present a new technique that aims to overcome these difficulties by using various observations as constraints for a physical model that then provide a 3D estimate of the feature’s structure.
In situ observations, such as spacecraft transits, can directly observe only a narrow slice of the phenomenon, whereas ground-based images compress the dimensionality into their plane of observation.Ĭlayton et al. Source: Journal of Geophysical Research: Space PhysicsĪ persistent obstacle to a more complete understanding of Earth’s auroral activity is characterizing the structure of auroral arcs in 3D.
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