The EFW (Electric Field and Waves) is part of the Wave Experiment Consortium (WEC). It consists of four 8 cm diameter spherical probes extended on 42.5 m long wire booms (88 m tip-tip) in the spacecraft spin plane. The probes are used for measuring either electric fields or plasma density variations. In the electric field mode, the probes are actively controlled by a bias current to ensure a high quality measurement. In the density mode, the probes are voltage biased to collect the ambient thermal electron current.
Analog signals from the EFW instrument are fed to STAFF, WHISPER and WBD. Commands to EFW and telemetry from EFW are passed through DWP. In addition, EFW receives (via DWP) signals from FGM and STAFF, and delivers (via DWP) the measured spacecraft potential to ASPOC.
The instrument may sweep the current or voltage of a probe to obtain a current-voltage characteristic useful for both instrument and plasma diagnostics.
Details on how to determine if EFW was sweeping during a particular interval may be found on the ''Users Guide to the Cluster Science Data System''.
There are a number of signals within the instrument which may be sampled at various frequencies and sent to telemetry. Basically the individual probe current Ii (in density mode) or voltage Vi (in electric field mode) as well as potential differences between probes Vij (in electric field mode) may be sampled at rates between 5 and 36000 s^-1. Typically, individual probe signals Vi are sampled at 5 s^-1. Potential differences Vij are sampled at 25 s^-1 in spacecraft normal mode NM) telemetry speed and at 450 s^-1 in burst mode BM).
This description has been obtained from Section 3.9 of the ''Users Guide to the Cluster Science Data System'', DS-MPA-TN-0015.
Version:2.4.0
The EFW (Electric Field and Waves) is part of the Wave Experiment Consortium (WEC). It consists of four 8 cm diameter spherical probes extended on 42.5 m long wire booms (88 m tip-tip) in the spacecraft spin plane. The probes are used for measuring either electric fields or plasma density variations. In the electric field mode, the probes are actively controlled by a bias current to ensure a high quality measurement. In the density mode, the probes are voltage biased to collect the ambient thermal electron current.
Analog signals from the EFW instrument are fed to STAFF, WHISPER and WBD. Commands to EFW and telemetry from EFW are passed through DWP. In addition, EFW receives (via DWP) signals from FGM and STAFF, and delivers (via DWP) the measured spacecraft potential to ASPOC.
The instrument may sweep the current or voltage of a probe to obtain a current-voltage characteristic useful for both instrument and plasma diagnostics.
Details on how to determine if EFW was sweeping during a particular interval may be found on the ''Users Guide to the Cluster Science Data System''.
There are a number of signals within the instrument which may be sampled at various frequencies and sent to telemetry. Basically the individual probe current Ii (in density mode) or voltage Vi (in electric field mode) as well as potential differences between probes Vij (in electric field mode) may be sampled at rates between 5 and 36000 s^-1. Typically, individual probe signals Vi are sampled at 5 s^-1. Potential differences Vij are sampled at 25 s^-1 in spacecraft normal mode NM) telemetry speed and at 450 s^-1 in burst mode BM).
This description has been obtained from Section 3.9 of the ''Users Guide to the Cluster Science Data System'', DS-MPA-TN-0015.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | PrincipalInvestigator | spase://CNES/Person/CDPP-Archive/Mats.Andre |