The Relationship Between Large Scale Thermospheric Density Enhancements and the Spatial Distribution of Poynting Flux. Issue 5 (3rd May 2021)

• Record Type: Journal Article
• Authors: Billett, D. D.; Perry, G. W.; Clausen, L. B. N.; Archer, W. E.; McWilliams, K. A.; Haaland, S.; Reistad, J. P.; Burchill, J. K.; Patrick, M. R.; Humberset, B. K.; Anderson, B. J.
• Is Part Of: Journal of geophysical research. Volume 126:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-03
• Subjects: AMPERE -- CHAMP -- ionosphere‐thermosphere coupling -- Poynting flux -- SuperDARN -- thermospheric density; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2021JA029205
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Large thermospheric neutral density enhancements in the cusp region have been examined for many years. The Challenging Minisatellite Payload (CHAMP) satellite for example has enabled many observations of the perturbation, showing that it is mesoscale in size and exists statistically over solar cycle timescales. Further studies examining the relationship with magnetospheric energy input have shown that fine‐scale Poynting fluxes are associated with the density perturbations on a case‐by‐case basis, whilst others have found that mesoscale downward fluxes also exist in the cusp region statistically. In this study, we use nearly 8 years of the overlapping Super Dual Auroral Radar Network and Active Magnetosphere and Planetary Electrodynamics Response Experiment datasets to generate global‐scale patterns of the high‐latitude and height‐integrated Poynting flux into the ionosphere, with a time resolution of 2 min. From these, average patterns are generated based on the interplanetary magnetic field orientation. We show the cusp is indeed an important feature in the Poynting flux maps, but the magnitude does not correlate well with statistical neutral mass density perturbations observed by the CHAMP satellite on similar spatial scales. Importantly, the lack of correlation between mesoscale height‐integrated Poynting fluxes and the cusp neutral mass density enhancement gives possible insight into other processes that may account for the discrepancy, such as energy deposition at finer scale sizes or at higher altitudes than captured. Key Points: Statistical patterns of the total downward Poynting flux into the atmosphere have been derived using Super Dual Auroral Radar Network and Active Magnetosphere and Planetary Electrodynamics Response Experiment data Statistical patterns of neutral mass density perturbations as a percentage of the background density have been derived using Challenging Minisatellite Payload data Mesoscale downward Poynting flux in the cusp region do not correlate very well with neutral mass density enhancements at a similar scale