MMS 2: Electric Field Power Spectral Density from Double Probes, 16 s Slow Mode

The Magnetospheric Multiscale (MMS) mission's Digital Signal Processor computes electric field power spectral density (EPSD) onboard. Data is derived from 1024-point FFTs on signals from Axial and Spin-Plane Double Probes, with spectra reported at rates from 16 per second to one every 16 seconds. This Level 2 product is provided by NASA, with a metadata last update date of 2026-03-13.

Use Cases

• Analyze plasma wave emissions based on the 56 pseudo-logarithmic frequency bins mentioned in the description
• Determine plasma density with ~3% accuracy based on narrow-band emission fitting described
• Study electric field dynamics in space based on power spectra calculated from ADP and SDP probe signals
• Investigate signal processing and averaging techniques based on the described 48-bit accuracy and 8-bit compression

Strengths

• Spectra calculated via a 1024-point FFT algorithm with a Hanning window, providing detailed frequency analysis
• Data has a dynamic range of over 120 dB with ~5% precision due to pseudo-logarithmic compression
• Nine signals can be processed simultaneously, with six at 100% duty cycle and three at 6.25% duty cycle

Limitations

• Timing between channels can be inaccurate by a fraction of a second as components are not synchronized
• Column-level documentation is absent; field semantics must be inferred after download
• Row count and file formats are unknown, which may limit suitability assessment

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Computed onboard the MMS spacecraft by a Digital Signal Processor (DSP) from analog signals of Axial and Spin-Plane Double Probes.

Time Range

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Freshness

Last updated 2026-03-13 06:21:19.019130; freshness should be verified

Geography

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