Summary
The educational UI explains a small cached slice of `MMS4_MEC_BRST_L2_EPHT89D`, a NASA CDAWeb/HAPI product for MMS4 magnetic ephemeris and support data. The note defines the terms that visitors encounter while reading a selected sample.
Key Facts
- NASA MMS describes Magnetospheric Multiscale as a mission of four spacecraft studying Earth's magnetosphere and magnetic reconnection.
- CDAWeb dataset notes describe the MEC product family as magnetic ephemeris and support data.
- HAPI metadata defines displayed fields including magnetic latitude, magnetic local time, Kp, Dst, GSM position, GSM velocity, and field-line type.
- NASA SPDF SSCWeb defines GSM as an Earth-centered coordinate system with X from Earth to Sun, Y perpendicular to the magnetic dipole, and X-Z containing the dipole axis.
- NOAA SWPC's Planetary K-index product is the public reference used for Kp as a planetary geomagnetic activity index.
Applied in the Build
The UI distinguishes measured or ephemeris quantities from model-context quantities. Position and velocity come from ephemeris; Kp, Dst, and field-line type are support or model-context fields in this product.
The term copy keeps storm language conservative and explains GSM, magnetic local time, Kp, Dst, and field-line type at the point of use.
Citation
Primary source: https://cdaweb.gsfc.nasa.gov/hapi/info?id=MMS4_MEC_BRST_L2_EPHT89D
Supporting sources: NASA MMS mission, CDAWeb dataset notes, NASA SSCWeb coordinate guide, NOAA SWPC Planetary K-index.
Build note: `mms4/research/mms-ephemeris-terms.md`