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Home > Research > Space Plasmas > Space instrumentation > Contribution to space missions > Parker Solar Probe/SWEAP

Parker Solar Probe/SWEAP

The SWEAP (Solar Wind Electrons Alphas and Protons) particles instrument is one of four instruments of the Flagship mission of NASA Parker Solar Probe. It is able to characterize the solar wind and in particular the non-adiabatic nature of its propagation from 10 solar radii, when the wind is super Alfvenic. One of the challenges will be to understand the anisotropy of the temperature distributions and monitor the heat flow at a short distance from the sun. To achieve this ambitious scientific program, SWEAP consists in a Faraday cup pointing to nadir and three plasmas spectrometers, two of which are dedicated to the measurement of electrons, SPAN-Ae and B-SPAN. These sensors are colored in yellow in Figure below.

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Solar Probe Plus the SWEAP sensors in yellow
crédit: Kasper et al., 2015

 LPP Team:

M. Berthomier, J. D. Techer

 Selected publications:

J. Kasper, R. Abiad, G. Austin, M. Balat-Pichelin, S. Bale, J. W. Belcher, P. Berg, H. Bergner, M. Berthomier, et al., Solar Wind Electrons Alphas and Protons Investigation: Design of the solar wind and coronal plasma instrument for Solar Probe Plus, Space Sci. Rev., 2015.

 Description of the instrument

The electron spectrometers in which LPP is involved consist in an inlet deflector that scan electrons arrival directions in a polar angle of ± 45 °, and a "top-hat" energy analyzer with a resolution of 10% covering 1eV-5keV in energy. Their geometry factor is adjustable and the cylindrical symmetry of the instrument allows instant cover of all azimuths. The detector, consisting of superposed microchannel plates (MCP), amplifies the signal associated with each incident electron. The charge cloud associated with electron impact on MCP is collected by a pixelated anode, each pixel corresponds to a particular azimuthal angle. This electrical pulse is processed by a charge amplifier ASIC enabling high speed electrons counting.

LPP provides the integrated detection electronics of the electron spectrometers. The scientific stakes are high because the quality of the electron distribution function estimate depends directly on the angular resolution which has to be maximized. The electronics is based on an ASIC analog channel 16 / digital configurable by the DPU of the instrument. This component was developed as part of the Solar Orbiter mission by LPP. It gives an angular resolution of 3-4 ° in the direction of the magnetic field. The spatial qualification was obtained in 2015. The detector also uses the technology developed by LPP to reduce to a single printed circuit the entire detection system while the standard design used three separate circuits. The LPP has worked with UC Berkeley to optimize this design and to adapt the detector to the electronics. The flight models have been built in 2016 and the calibration of the spectrometers is underway.


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Tutelles : CNRS Ecole Polytechnique Sorbonne Université Université Paris Sud Observatoire de Paris Convention : CEA
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