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Potential control device (PCD)

NSSDCA ID: 1997-075B-06

Mission Name: Equator-S
Principal Investigator:Dr. Klaus M. Torkar


The purpose of the PCD is to reduce the spacecraft potentials to a few volts, levels sufficiently low to allow plasma particle measurements down to very low energies. For this purpose, the PDC emits beams of 6 keV indium ions to compensate the positive charging that would otherwise exist under most circumstances. The emission principle is field evaporation and ionzation of the liquid metal covering a needle by applying a high voltage. Beam currents are variable and can either be set to fixed values, or are adjusted automatically based on the electron energy spectrum measured by the 3DA instrument that is transmitted to PCD in real-time. PCD is identical to the ASPOC instrument developed for CLUSTER.

Alternate Names

  • Equator-S/PCD
  • PCD

Facts in Brief

Mass: 2.6 kg
Power (avg): 2.8 W


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Klaus M. TorkarLead InvestigatorAustrian Academy of
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