NSSDCA ID: 2007-004A-02
Mission Name: THEMIS-AThe Electrostatic analyzer (ESA) measures the thermal ion and electron fluxes in a 360 degree field of view over the energy range 3-30 keV. It is a "top hat" back-to-back pair of hemispherical ESAs that were built at UCB following the heritage of similar instruments on AMPTE/IRM, Giotto, FAST, Wind and CLUSTER. ESA measures plasma moments to within 10%, at high time resolution (10s or better) for interprobe timing studies, and it also measures instantaneous differences in velocity and ion pressure between probes, to estimate the scale size of transport, the size and strength of flow vortices and the pressure gradient. Both the ion and the electron ESA have a look direction of 180 degrees in elevation, split in eight bins (one per anode). The particles are selected in E/q (where q is the charge) by a sweeping potential applied in 32 steps, 32 times/spin (32 azimuths) between the outer and inner concentric spheres. On-board moment, pitch angle and averaging computations are implemented at the IDPU. These operations routinely utilize FGM data and SST data (to ensure correct values when the peak flux extends beyond the plasma instrument energy range).
Questions and comments about this experiment can be directed to: Dr. Dieter K. Bilitza
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Charles W. Carlson | Co-Investigator | University of California, Berkeley | cwc@ssl.berkeley.edu |