DMSP Poynting Flux: Data Processing and Inter-Spacecraft Comparisons

Area of Science:

• Space Physics
• Magnetosphere-Ionosphere Coupling
• Space Weather

Background:

• Poynting flux (PF) quantifies energy transfer between the magnetosphere and ionosphere.
• Low Earth orbit spacecraft provide in situ measurements of ion drift and magnetic fields for PF calculations.
• Defense Meteorological Satellite Program (DMSP) data offers a valuable historical record but requires careful preprocessing for research.

Purpose of the Study:

• To develop and validate an automated approach for calculating earthward Poynting flux (PF) from DMSP data.
• To create a comprehensive PF dataset using extensive DMSP observations.
• To analyze the impact of using full-field components versus single-component approximations in PF calculations.

Main Methods:

• Developed an automated data preprocessing and quality control pipeline for DMSP ion drift and magnetic field measurements.
• Calculated quasi-steady earthward PF using nine satellite-years of DMSP F15, F16, and F18 data.
• Validated the method through inter-comparison of PF from different spacecraft using over 2,000 magnetic conjunction events.
• Applied an equal-area binning technique to derive average spatial patterns of PF and related parameters (magnetic perturbation, electric field, ion drift velocity).
• Analyzed the influence of using all electric and magnetic field components compared to typical single-component approximations.

Main Results:

• The automated approach for calculating PF from DMSP data was validated, showing no significant systematic differences between spacecraft.
• A comprehensive PF dataset was produced from DMSP F15, F16, and F18 observations.
• Analysis using full-field components revealed increased relative strength of near-cusp PF and a ~25% increase in integrated high-latitude PF compared to single-component approximations.

Conclusions:

• The developed automated method provides a reliable way to calculate earthward Poynting flux from DMSP data.
• The study highlights the importance of utilizing full-field components in electric and magnetic measurements for accurate PF calculations.
• The findings improve our understanding of energy transfer processes between the magnetosphere and ionosphere.