24, July 2014

PROJECT TITLE: Cluster/HIA in-flight calibration and data quality improvement for scientific exploitation – CALYPSO

Coordinator: Institute of Space Science (ISS) 


Period: 29 November 2013 – 18 November 2016

Project director: Dr. Adrian Blagau

Project team:

  • 5 Ph. D. researchers
  • 1 senior electrical engineer
  • 2 young scientist

Description: Cluster: a ESA ‘cornerstone’ mission; launched in the summer of 2000, 4 identical S/C that make correlated measurements in space, to study phenomena in 3-D

HIA has the objective to measure the 3-D velocity distributions of ions. Plasma density, velocity, pressure tensor can than be derived.

HIA operates on C1 and C3.

The ions moving along different directions (different polar angle) in the plane of the HIA entrance aperture are deflected and focused by the EA on the exit plane, where they are recorded by a system of position encoding anodes Coverage in azimuthal angle is achieved by using the satellite spin.

In order to cover the whole range of particle fluxes specific to various plasma regeions, HIA has two sections of different sensibilities.

Due to various factors (e.g. exposure to radiation, detector aging, adjustments in operating parameters), the HIA detection efficiency changes over time, prompting for continuous in-flight calibration.

Project objectives:

HIA in-flight absolute calibration

  • This is done by comparing HIA and WHISPER density data on selected intervals
  • WHISPER uses different method to infer plasma density (by analyzing electric signals in the neighboring plasma)
  • HIA data from Nov. 2005 to Nov 2009 already calibrated at ISS between 2009 and 2011

Statistical comparisons between HIA and WHISPER density data in various plasma environments

  • all intervals from certain time epoch(s) will be considered for a statistical study
  • provide feed-back on the results obtained in O1
  • will show the instrument performance in magnetospheric regimes not used for calibration

Anode and energy dependence of HIA in-flight efficiency

  • The absolute calibration (O1) assumes that these dependences are well described by the coefficients determined on ground, before launch
  • The objective will investigate in-flight the anode and energy dependence of HIA efficiency, aiming at improving the in-flight calibration task beyond the absolute calibration procedure

In-flight calibration of He++ measurements provided by HIA

  • to calibrate in-flight the He++ plasma moments provided by HIA in solar-wind


  • Software development and set-up of a local data base (WP1 + WP2)
  • “Routine” HIA absolute calibration activities (WP1)

Contributions to the STAR programme objectives:

  • The results of CALYPSO have a direct impact on data quality provided by one instrument onboard the ESA Cluster mission
  • CALYPSO has a major relevance for the ESA Cluster Active Archive (CAA) Programme. The CAA preserves and makes freely available the properly calibrated, high-resolution Cluster data ( ~ 1800 users, ~ 3 TB monthly average download, ~ 0.6 TB for CIS data alone)
  • The project increases the group expertise in the field of particle instrumentation and strengthens the very good collaboration with well established institutions involved in hardware development.
  • CALYPSO ensures an favorable position for the group to conducting scientific research

Homepage: CALYPSO