The LANL 01A MPA data set contains numerical moments computed from measurements of the Los Alamos Magnetospheric Plasma Analyzer (MPA) [Bame et al., Rev. Sci. Inst., in press 1993]. The moments are presented in s/c coordinates: the z-axis is aligned with the spin axis, which points radially toward the center of the Earth; the x-axis is in the plane containing the spacecraft spin axis and the spin axis of the Earth, with +X generally northward; and the y-axis points generally eastward. Polar angles are measured relative to the spin axis (+Z), and azimuthal angles are measured around the z-axis, with zero along the +X direction. The moments are computed for three 'species': lop (low-ener. ions, ~1eV/e-~130eV/e); hip (hi-ener. ions, ~130eV/e-~45keV/e); alle (electrons, ~30eV - ~45keV ). The electron measurements are obtained 21.5 secs after the ion measurements. Epoch is the measurement time appropriate for the ions. The moments are computed after the fluxes are corrected for background and s/c potential. Algorithms for these corrections are relatively unsophisticated, so the moments are suspect during times of high background and/or high spacecraft potential. Because the determined spacecraft potential is not very precise, the magnitude of the low-energy ion flow velocity is probably not accurate, but the flow direction is well determined. Tperp and Tpara are obtained from diagonalization of the 3-dimensional temperature matrix, with the parallel direction assigned to the eigenvalue which is most different from the other two. The corresponding eigenvector is the symmetry axis of the distribution and should be equivalent to the magnetic field direction. The eigenvalue ratio Tperp/Tmid, which is provided for each species, is a measure of the symmetry of the distribution and should be ~1.0 for a good determination. Several of the parameters have a fairly high daily dynamic range and for survey purposes are best displayed logarithmically. These parameters are indicated by non-zero 'SCALEMIN' values in this file. A quality flag value of 1 indicates that the values are suspect because of unreliable location info.

This is the time of the proton data collection (electrons 21.5 seconds later). Universal Time in data cell: day, month, year hour, min, seconds. Ex: '01-Jan-1981 00:00:00.000'.

This is the time of the proton collection (electrons 21.5 seconds later). Time in the format: year, day of year, and second of the same day.

Partial density of low energy ions (1-130 eV/e).

LANL 01A MPA velocity vector low-enery Ions (1-130 eV/e) in spacecraft Coordinates in units of km/s.

Temperature of low energy ions (1-130 eV/e).

Ratio of temperature (Tperp/Tmid) of low energy ions (1-130 eV/e).

Spacecraft MPA partial density of high energy ions (.13-45 keV/e).

Velocity vector high-enery protons (.13-45 keV/e) in spacecraft Coordinates in units of km/s.

Spacecraft MPA temperature of high energy ions (.13-45 keV/e).

Proton symmetry axis: polar angle relative to Earth direction, azimuthal angle from the north.

Ratio of temperature (Tperp/Tmid) of low energy ions (.13-45 keV/e).

Partial density of electrons (.03-45 keV/q).

Temperature of electrons (.03-45 keV/q).

Electron symmetry axis: polar angle relative to Earth direction, azimuthal angle from the north.

Ratio of temperature (Tperp/Tmid) of electrons (.03-45 keV/q).

Spacecraft potential in units of volts.

Background Count Rate.

Spacecraft position, polar geographic coordinates (radius,lat,long).

Spacecraft position, cartesian coordinates (radius,lat,long). Geocentric Celestial Inertial, is earth centered, with the X-axis pointing from the Earth towards the first point of Aries (the position of the Sun at vernal equinox). This direction is the intersection of the Earth's equatorial plane and the ecliptic plane--thus the X-axis lies in both planes. The Z-axis is parallel to the rotation axis of the Earth, and the Y-axis completes a right-handed orthogonal coordinate system. The X-axis is the direction of the mean vernal equinox of J2000. This is a virtual variable generated by read_myCDF w/ useof the data in the sc_pos_geo variable and a conversion routinespecified in the function attribute, namely conv_pos.

Spacecraft position, polar magnetic coordinates (radius,lat,long).

Data quality flag. Data quality flag, 0 = ok, 1 = Results unreliable.

Data gap flag. Data gap flag, 0 = No Gap, 10 = No data available.

Time offset for electron measurements. Electron sample time is 21.5 seconds after that of ions.