Polar EFI: Spacecraft Potential and Plasma Density Measurements

Spacecraft potential and plasma density data from the Polar satellite's Electric Fields Instrument, provided at realtime resolution. The plasma density is derived from a function fitted to POLAR Hydra particle data from April 1, 2001, with relative accuracy estimated at 10-30% depending on plasma conditions. The dataset is produced by the National Aeronautics and Space Administration and was last updated in March 2026.

Use Cases

• Modeling spacecraft charging behavior based on spacecraft potential measurements.
• Analyzing plasma density fluctuations in the magnetosphere based on the derived density function.
• Calibrating or validating other plasma instrument readings using the estimated accuracy bounds.
• Studying short-term plasma dynamics using the realtime resolution data.

Strengths

• Plasma density values have a defined relative accuracy of 10-30% on short time scales.
• Absolute accuracy is better than a factor of two for densities less than about 20 particles/cm^3.
• Clear data quality flags: filler values (1.0e+20, 1.0e-20) indicate unreliable or out-of-bounds calculations.
• All spacecraft potential values are flagged as true values with no filler data.

Limitations

• Plasma density values greater than 30 particles/cm^3 are described as inaccurate and are not plotted.
• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Data from the Polar satellite's Electric Fields Instrument; plasma density derived from a function fitted to POLAR Hydra particle data.

Time Range

The calibration function is based on data from 2001/04/01; temporal coverage of the full dataset is not specified.

Freshness

Last updated 2026-03-13 05:28:48.018482; freshness should be verified.

Geography

Data collected in space, likely within Earth's magnetosphere, by the Polar spacecraft.