Abstract
The two-dimensional electron spectrometer onFreja consists of a ‘top-hat’-type electrostatic analyzer with the addition of entrance aperture deflection plates. The field of view of the concentric-hemisphere analyzer is modified from a plane to a cone up to 25° from this plane by application of bipolar high voltages to the deflection plates. Fast high-voltage sweeps allow full 10 eV–25 KeV, 500-point distribution function measurements in 32 ms. Constant-energy or limited energy-sweep modes allow time resolutions down to 1 ms.
A set of electronics combines the electron data with F4 wave data to allow on-board calculations of cross-correlations between electron fluxes and wave electric fields. Additionally, a fast signal processor is capable of searching the electron pulse sequence from one or several channeltrons for high-frequency modulations in the electron flux.
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Boehm, M., Paschmann, G., Clemmons, J. et al. The TESP electron spectrometer and correlator (F7) on Freja. Space Sci Rev 70, 509–540 (1994). https://doi.org/10.1007/BF00756884
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DOI: https://doi.org/10.1007/BF00756884