DMSP Poynting Flux: Data Processing and Inter‐Spacecraft Comparisons

Abstract

Poynting flux (PF) calculated from low Earth orbit spacecraft in situ ion drift and magnetic field measurements is an important measure of energy exchange between the magnetosphere and ionosphere. Defense Meteorological Satellite Program (DMSP) spacecraft provide an extensive back‐catalog of ion drift and magnetic perturbation measurements, from which quasi‐steady PF could be calculated. However, since DMSP are operations‐focused spacecraft, data must be carefully preprocessed for research use. We describe an automated approach for calculating earthward PF focusing on pre‐processing and quality control. We produce a PF data set using nine satellite‐years of DMSP F15, F16, and F18 observations. To validate our process we inter‐compare PF from different spacecraft using more than 2,000 magnetic conjunction events. We find no serious systematic differences. We further describe and apply an equal‐area binning technique to obtain average spatial patterns of PF, magnetic perturbation, electric field and ion drift velocity. We perform our analysis using all components of electric and magnetic field and comment on the adverse consequences of the typical single‐electric‐field‐component DMSP PF approximation on inter‐spacecraft agreement. Including full‐field components significantly increases the relative strength of near‐cusp PF and increases the integrated high‐latitude PF by ∼25%.

Inter‐Hemispheric Energy Input Into the Ionosphere‐Thermosphere System During Magnetic Storms: What We Can and Cannot Learn From DMSP Observations

“…Knipp et al (2021) used the in-track component of ion drift measured by DMSP in the Poynting flux calculations. Although this approach can improve Poynting flux estimates in general cases (Kilcommons et al, 2022), it can introduce some data coverage constraints because such data can have large error levels (Drayton et al, 2005), and are usually not recommended for use (Huang & Burke, 2004). However, the use of the in-track ion drift velocity with at least good quality in our Poynting flux calculations would severely limit our study regarding the number of events, particularly in the case of severe and extreme magnetic storms.…”

Poynting Flux Input to the Auroral Ionosphere: The Impact of Subauroral Polarization Streams and Dawnside Auroral Polarization Streams

“…The Poynting flux S p has been computed using Equation , where the perturbation magnetic field comes from DMSP's fluxgate magnetometer (Rich, 1984) and the electric field is inferred from E = ‒ v × B 0 (the corotation electric field has been subtracted; see Kilcommons et al. (2022)). Here B 0 is the International Geomagnetic Reference Field and v is the ion bulk flow in the Earth frame (satellite velocity has been subtracted).…”