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Subsections

• General
• Data

UKS Prime Parameter Database

General

Processed data from UKS were originally stored at the UK Geophysical Data Facility at RAL, under a propriatary database system (R-EXEC). The database was regenerated circa 1992 and deposited at the World Data Centre at RAL, superseding the original GDF holdings. These data have subsequently been converted into Common Data Format (CDF) files, whose detailed design structure matches closely those intended for the Cluster mission and defined in DS-QMW-TN-0003 (available from http://www.space-plasma.qmw..ac.uk/). In some cases, raw data was reprocessed and placed directly in the CDHF database. The database team decided to implement a faithful archive of any original GDF/WDC data, resulting in a mixture of products rather than a completely uniform dataset. This mixed pedigree has resulted in some anomalies, of which the most important, perhaps, is the interpretation of the timetags for the data. The GDF and WDC database labelled each datum with the start time of the data integration period, placed on exact $0, 5, 10, \ldots$second boundaries. The Cluster specification is based on centred timetags, so that newly deposited data has a different definition of the timetags. Users should consult the Data Caveats page for accurate information, and may need to adjust the timetags for some purposes. There are also differences in the way the IRM timetags were generated, including both mission operational and database generation aspects. These are also detailed in the Data Caveats page, and discussed briefly below in conjunction with the IRM Prime Parameter data.

The CDHF has not maintained the various catalogues used in conjunction with the GDF. An Appendix to this document describes all the UKS data variables. The UKS-IRM positional information has been converted into CDF files which are held with the data.

UKS Prime Parameter data may be accessed using a WWW interface at http://XXX.XXX.XXXX/ and also through the client-server X-Chooser system available through the same WWW location.

Data

The databases contains seven different types of data product derived from four instruments as detailed below. No data are available from the particle correlator. Vectors are stored in geocentric-solar-ecliptic (GSE) coordinates. Time tags on data records denote either the start of the integration period or the centre thereof (see the Data Caveats page for more information). Details of units, instrument modes, and other ``metadata'' information is held within the CDF files. Some of this information is repeated in an Appendix to this document.

• Magnetometer. 5 second mean values of the magnetic field
• Ion spectrometer. Spin-average (approximately 5 seconds) values of various moments of the ion distribution:
  • for ``fast time resolution" (FTR) data: ion number density, velocity and temperature plus some quality factors. This data is based on full $4\pi$ster-radian coverage, although for some solar wind modes a single $45^\circ$(corresponding to anti-sunward flow velocities) sector is missing.
  • for ``solar wind" (SW) data: proton number density, velocity and temperature and, in some cases, alpha-particle number density, velocity and temperature. Plus some quality factors.

  In some cases the ion data have a resolution of around 10 seconds. This indicates that data are available only for alternate spins, i.e. that the data value corresponds to an integration over 1 spin starting at the time tag and that there is a 1 spin deadtime before the next data value.

• Electron spectrometer. 5 second average values of various moments of the electron distribution (number density, temperature parallel and perpendicular to the magnetic field, number flux, heat flux) and of the electron distribution perpendicular to the magnetic field. Not available for all modes of the instrument.
• Wave spectrometer.
  • for ``autocorrelator" data: approximately 5 second mean values of the power spectral density at 52 frequencies between 0.11 and 3.9 kHz.
  • for ``swept-frequency analyser" data: approximately 1 minute mean values of the power spectral density at 256 frequencies between 0.392 and 132 kHz.
  • for ``power" data: approximately 5 second average and peak values of the wave power in the frequency range between 0.11 and 3.9 kHz.

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