The Plasma Electrons and Currents Experiment (PEACE) data products consist of prime and summary parameters (moments). Collected from two instruments, a low-energy electron analyzer (LEEA) and a high-energy electron analyzer (HEEA), the 3-D and 2-D data products contain the measured quantity in a suitable array, i.e., count rate, particle flux, particle energy flux or phase space density.

The energy coverage is from 0.67 eV to 30 KeV in 92 levels. Both sensors can use the full range, but the HEEA will normally operate over a higher energy range than the LEEA. Each sensor covers the range 0--180 degrees with respect to the spin axis, and they are mounted opposite each other with a view perpendicular to the spin axis, thus covering the complete angular range in a half rotation of the spacecraft. The field of view perpendicular to the fan is 2 degrees for the LEEA and 5.6 degrees for the HEEA. Energy resolution (Delta-E)/E is 0.13 for LEEA and 0.16 for HEEA. There are four sweep modes, synchronized to the spin period (4 s), to vary the azimuthal angular resolution.

Three categories of PEACE data are available from the Cluster Active Archive (CAA): three-dimensional distribution data, pitch angle distribution data, and electron moments data.

(I) A variety of 3-D data products are produced by PEACE, but only one standard reduced resolution (compressed by a factor of 8) 3-D data (3DR) is routinely produced with a standard size that is independent of sweep mode. Other 3-D data include the flexible reduced polar resoluttion (3DXP); full resolution 3-D distributions (3DX, occasionally 3DXLAR for the "summed energy" data); and partial azimuth content data (3DXPA, 3DXPALAR).

(II) Pitch angle distribution data include the standard spin rate pitch angle data (PITCH_SPIN), full time resolution pitch angle data (PITCH_FULL), and pitch angle data from various 3-D data (PITCH_3DR, PITCH_3DX, PITCH_3DXLAR, PITCH_3DXA, 3DXA_LAR).

(III) For the electron moments data, the CAA provides the Prime Parameters which have some inherent limiations and the MOMENTS data which offer the highest quality moments, though not always at spin rate.

The MOMENTS are Summary Parameters from 3-D data that include electron density, velocity vector, pressure tensor and heat flux vector. The vectors and tensors are provided in GSE coordinates. Velocity and temperature are also provided as components perpendicular and parallel to the magnetic field (where the magnetic field data is taken from CSDS FGM PP data, at present). Moments production software is provided by the PEACE team via the CAA to allow scientists to calculate their own moments if they wish, for example using a subset of the measured energies and polar zones.

The Prime Parameters (PP) are derived from the onboard moment sums, which are converted to electron moments data (density, velocity, perpendicular and parallel temperature, parallel heat flux). The PP data are provided in the GSE coordinate system. Geometric factor updates based on in-flight calibration are used to correct for errors due to the less up-to-date onboard calibrations. It is recommended that the CAA Moments data (Summary Parameters) and not the PP data are preferred for science analysis, despite the reduced time resolution in some cases, and that use of the PP data is only made after careful consideration of their limitations.

In addition to these three categories of products, there are onboard selected pitch angle data (PAD), onboard moments Sums (OMS) in both normal and burst modes, and other diagnostic data.

For more details, see Chapter 8 of "The Cluster Active Archive: Studying the Earth's Space Plasma Environment", edited by Dr. Harri Laakso, Matthew G. T. T. Taylor, C. Philippe Escoubet, from which this information was obtained.