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SPASE version 2.2.2
The following description applies to the Wideband Data (WBD) Plasma Wave Receivers on all four Cluster satellites, each satellite being uniquely identified by its number (1 through 4) or its given name (Rumba, Salsa, Samba, Tango, respectively). High time resolution calibrated waveform data sampled in one of 3 frequency bands in the range 0-577 kHz along one axis using either an electric field antenna or a magnetic search coil sensor. The dataset also includes instrument mode, data quality and the angles required to orient the measurement with respect to the magnetic field and to the GSE coordinate system. The AC electric field data are obtained by using one of the two 88m spin plane electric field antennas of the EFW (Electric Fields and Waves) instrument as a sensor. The AC magnetic field data are obtained by using one of the two search coil magnetometers (one in the spin plane, the other along the spin axis) of the STAFF (Spatio-Temporal Analysis of Field Fluctuations) instrument as a sensor. The WBD data are obtained in one of three filter bandwidth modes: (1) 9.5 kHz, (2) 19 kHz, or (3) 77 kHz. The minimum frequency of each of these three frequency bands can be shifted up (converted) from the default 0 kHz base frequency by 125.454, 250.908 or 501.816 kHz. The time resolution of the data shown in the plots is determined from the WBD instrument mode. The highest time resolution data (generally the 77 kHz bandwidth mode) are sampled at 4.6 microseconds in the time domain (~4.7 milliseconds in the frequency domain using a standard 1024 point FFT). The lowest time resolution data (generally the 9.5 kHz bandwidth mode) are sampled at 36.5 microseconds in the time domain (~37.3 milliseconds in the frequency domain using a standard 1024 point FFT). The availability of these files depends on times of DSN and Panska Ves ground station telemetry downlinks. A list of the status of the WBD instrument on each spacecraft, the telemetry time spans, operating modes and other details are available under Science Data Availability on the University of Iowa Cluster WBD web site at http://www- pw.physics.uiowa.edu/cluster/ and through the documentation section of the Cluster Active Archive (CAA) (http://caa.estec.esa.int/caa). Details on Cluster WBD Interpretation Issues and Caveats can be found at http://www- pw.physics.uiowa.edu/cluster/ by clicking on the links next to the Caution symbol in the listing on the left side of the web site. These documents are also available from the Documentation section of the CAA website. For further details on the Cluster WBD data products see Pickett, J.S., et al., "Cluster Wideband Data Products in the Cluster Active Archive" in _The Cluster Active Archive_, 2010, Springer-Verlag, pp 169-183, and the Cluster WBD User Guide archived at the CAA website in the Documentation section. ...
CALIBRATION: ... The procedure used in computing the calibrated Electric Field and Magnetic Field values found in this file can be obtained from the Cluster WBD Calibration Report archived at the CAA website in the Documentation section. Because the calibration was applied in the time domain using simple equations the raw counts actually measured by the WBD instrument can be obtained by using these equations and solving for 'Raw Counts', keeping in mind that this number is an Integer ranging from 0 to 255. Since DC offset is a real number, the resultant when solving for raw counts will need to be converted to the nearest whole number. A sample IDL routine for reverse calibrating to obtain 'Raw Counts' is provided in the WBD Calibration Report archived at the CAA. ...
CONVERSION TO FREQUENCY DOMAIN: ... In order to convert the WBD data to the frequency domain via an FFT, the following steps need to be carried out: 1) If Electric Field, first divide calibrated data values by 1000 to get V/m; 2) Apply window of preference, if any (such as Hann, etc.); 3) Divide data values by sqrt(2) to get back to the rms domain; 4) perform FFT (see Bandwidth variable notes for non-continuous modes and/or the WBD User Guide archived at the CAA); 5) divide by the noise bandwidth, which is equal to the sampling frequency divided by the FFT size (see table below for appropriate sampling frequency); 6) multiply by the appropriate constant for the window used, if any. These steps are more fully explained in the WBD Calibration Report archived at the CAA....
| Bandwidth | Sample Rate | |
|---|---|---|
| 9.5 kHz | 27.443 kHz | |
| 19 kHz | 54.886 kHz | |
| 77 kHz | 219.544 kHz |
COORDINATE SYSTEM USED: ... One axis measurements made in the Antenna Coordinate System, i.e., if electric field measurement, it will either be Ey or Ez, both of which are in the spin plane of the spacecraft, and if magnetic field measurement, it will either be Bx, along the spin axis, or By, in spin plane. The user of WBD data should refer to the WBD User Guide, archived at the CAA, Section 5.4.1 and Figure 5.3 for a description of the three orientation angles provided in these files. Since WBD measurements are made along one axis only, these three angles provide the only means for orienting the WBD measurements with respect to a geocentric coordinate system and to the magnetic field direction ...
Cluster WBD Instrument page maintained by the University of Iowa with links to instrument descriptions and team members, publications, lists of coordinated observing times, science data availability catalogs, data, data interpretation and caveat descriptions as well as data analysis tools.
Cluster WBD documentation with links to lists of coordinated observing times, science data availability catalogs, WBD User Guide, WBD Calibration Report, WBD Interface Control Document, and data interpretation and caveat descriptions.
Users of the Cluster WBD data are encouraged to acknowledge Jolene S. Pickett, PI and Donald A. Gurnett, Co-I University of Iowa and the Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center, or the Cluster Active Archive, as appropriate, as the source of the data in any publication.
| Role | Person | |
|---|---|---|
| 1. | Principal investigator Technical contact |
Ms. Jolene S. Pickett |
| 2. | CoInvestigator FormerPI |
Prof. Donald A. Gurnett |
FTP access to repository of Cluster 1 WBD CDFs at NASA CDAWeb.Name of the data resource: C1_WAVEFORM_WBD
Repository of Cluster 1 WBD data in CDF format at NASA CDAWeb, accessible via web interface. Name of the data resource: C1_WAVEFORM_WBD.
Users of the Cluster WBD data are encouraged to acknowledge Jolene S. Pickett, PI and Donald A. Gurnett, Co-I University of Iowa and the Coordinated Data Analysis Web (CDAWeb) at the NASA Goddard Space Flight Center, as the source of the data in any publication.
Access to repository of Cluster 1 Wideband data in Cluster Exchange Format (CEF) at the Cluster Active Archive
Users of the Cluster WBD data are encouraged to acknowledge Jolene S. Pickett, PI and Donald A. Gurnett, Co-I University of Iowa and the Cluster Active Archive, as appropriate, as the source of the data in any publication.
See the Cluster WBD WBD data Interpretation Issues and Caveats documents at the web site http://www-pw.physics.uiowa.edu/cluster/ , and clicking on the links next to the "Caution" symbol in the listing on the left hand side of the page. The documents can also be retrieved from the Documentation section of the CAA.
UT Time, time of WBD data point. On-board time is corrected to a precision of order 50 microseconds when compared to UTC. The applied time correction comes from the DWP TCOR time correction files located at the Cluster Active Archive (CAA).
Frequency Bandwidth: 9.5 kHz, 19 kHz, 77 kHz. WARNING: 19 and 77 kHz Bandwidth modes with 8-bit resolution, and 77 kHz Bandwidth mode with 4-bit resolution (see Resolution variable) are not continuous data modes. Always check for periodic time jumps for these modes.
Base freq. of freq. bandwidth (0.0, 125.454, 250.908, and 501.816 kHz) - Also known as Conversion Frequency.
Number of bits used when digitizing waveform (8-bit, 4-bit, or 1- bit)
Antenna (0=Ez, 1=Bx, 2=By, 3=Ey)
Gain state of WBD instrument. Steps of 5 dB from 0 to 75.
Total angle between antenna used for WBD measurement and measured B field direction. Antenna refers to the antenna in use, either E or B. See ANTENNA variable.
Total angle between the Xgse axis and the antenna direction. Antenna refers to the antenna in use, either E or B. See ANTENNA variable.
Total angle between Ygse axis and the projection of the antenna direction in the Ygse-Zgse plane, measured counter-clockwise from +Ygse (angle=0 deg) to +Zgse (angle=90 deg), -Ygse (angle=180 deg) and -Zgse (angle=270 deg). Antenna refers to the antenna in use, either E or B. See ANTENNA variable.
DC Offset used when converting from raw digital values to calibrated data. DC Offset values may be used to reverse calibrate the data to the original raw counts and to determine the boundaries of the original transport packets.
Calibrated AC WBD Electric Field
Calibrated AC WBD Magnetic Field.
Data Quality: 0 = OK, 1 = clipped or questionable, 2 = bad data point. Clipped data: Measurement was equal to raw data value maximum (255) or minimum (0). This does not necessarily mean the receiver was in saturation, which would be accompanied by non-linear effects.
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The WBD (Wide Band Data) investigation is designed to provide high-resolution frequency/time spectra of plasma waves in the Earth's magnetosphere. As part of the Wave Experiments Consortium (WEC), this instrument provides measurements of both electric and magnetic fields in selected frequency bands from 25 Hz to 577 KHz. Continuous waveforms are digitized, formatted, and transferred to the spacecraft telemetry system using either a 220 Kbps real-time mode or a 73 Kbps burst mode. The real-time data require direct acquisition by a NASA Deep Space Network receiving station, and the burst-mode data are stored on the spacecraft tape recorder for later playback. On the ground the waveforms are Fourier transformed to provide high-resolution frequency/time spectrograms. The extremely high (microsecond) time resolution provided by the WBD measurements will make it possible to utilize the signals from two or more of the Cluster spacecraft to perform very-long-baseline-interferometer measurements. The WBD instrument processes signals from one of four selectable sensors: two electric field signals (from the EFW experiment) and two magnetic field signals (from the STAFF). The EFW sensors are spherical electric antennas with sphere-to-sphere separation of about 100 m after full deployment. The STAFF sensors are search coil magnetometers with the measurement axis in the spin plane (By) or along the spin axis (Bz). Commanding of the WBD instrument is managed by the DWP instrument. In the burst data recording mode, the WBD data are transferred to the DWP at 220 Kbps. Then the DWP reduces the wideband data by a factor of three by digital filtering and re-sampling, and sends the lower rate data to the spacecraft data system for recording and subsequent playback. For more details of the Cluster mission, the spacecraft, and its instruments, see the report ``Cluster: mission, payload and supporting activities,'' March 1993, ESA SP-1159, and the included article ``The Wideband Plasma Wave Investigation,'' by D. A. Gurnett et al., from which this information was obtained.
Information about the Wide Band Data (WBD) experiment on the Cluster 2/FM5 (Rumba) mission.
| Role | Person | |
|---|---|---|
| 1. | Principal investigator | Prof. Donald A. Gurnett |
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This Cluster II spacecraft, FM5 (Rumba), is also known as Phoenix, after a mythical Arabian bird which was burnt on a funeral pile and then rose from the ashes to live again. The original Cluster of four spacecraft experienced a launch failure in 1996. (NSSDC will carry the name "Cluster96" in its information files to designate the unsuccessful 1996 four-spacecraft Ariane 5 launch.)
Phoenix was approved in July 1996 as a replacement for the lost four-spacecraft group. It was later (April 1997) agreed that the potential science return from a full Cluster reflight was so important that a further three near-replicas of the original spacecraft would also be built.
This Cluster II spacecraft, FM5 (Rumba), was launched together with FM8 (Tango) by a Soyuz-Fregat rocket from Baikonur. The four similar spacecraft of the Cluster II mission are part of ESA's and NASA's Solar-Terrestrial Science Program (STSP). The purpose of the Cluster II mission is to study small-scale structures in three dimensions in the Earth's plasma environment, such as those involved in the interaction between the solar wind and the magnetospheric plasma, in global magnetotail dynamics, in cross-tail currents, and in the formation and dynamics of the neutral line and of plasmoids.
The four Cluster II spacecraft will orbit in a tetrahedral formation in near-polar orbits of nominally 4 x 19.6 Earth radii, with period about 57 hours, and inclination about 90.7 degrees. Relative distances between the spacecraft will be adjusted in the course of the mission, depending on the spatial scales of the structures to be studied, varying from a few hundred km to a few Earth radii. The tetrahedral formation is essential for making three-dimensional measurements and for determining the curl of vectorial quantities such as the magnetic field.
The orbits of all four spacecraft will be frequently maneuvered so as to achieve the targeted investigations. See http://jsoc1.bnsc.rl.ac.uk/pub/PlanningData.html for ongoing updates of orbital information and other status.
Each spacecraft will be spin-stabilized, normally at around 15 rpm, and will be cylindrical in shape, with a 2.9-m diameter and 1.3-m length. It will have two rigid 5-m radial experiment booms, four 50-m experiment wire booms, and two axial telecommunications antenna booms. Telemetry downlink bit rate will be 2 to 262 kbit/s.
Each spacecraft will have AC and DC magnetometers, an electric fields and waves sensor, an electron emitter/detector, an electron density sounder, electron and ion plasma analysers, an energetic particle detector, an ion emitter, and a data processing unit.
Cluster operations will be performed by ESOC in Darmstadt, Germany, with support from NASA's Deep Space Network. Cluster is also an IACG mission. The scientific data are distributed by ESOC using CD-ROM as a medium to the Principal Investigators, Co-Investigators and the network of eight national data centres (6 in Europe, 1 in USA and 1 in China) that form the Cluster Science Data System (CSDS). There are approximately 80 recipients world-wide. Science operations are carried out by the Joint Science Operations Centre, co-located with the UK data centre at RAL, Didcot. A wide scientific community will have differing rights of access to the Cluster data. Scientists wishing to access Cluster data should contact their national Data Centres.
The Cluster Summary Parameters are publicly available on CDAWeb at http://cdaweb.gsfc.nasa.gov/cdaweb/istp_public and the Prime Parameters are available on CDAWeb at http://cdaweb.gsfc.nasa.gov/cdaweb/ to project personnel (password-protected).
See the Cluster II WWW site at http://sci.esa.int/cluster/ for more information, including spacecraft and exprient status.
An article on 'The Resurrection of the Cluster Scientific Mission' was published in ESA Bulletin no. 91 (August 1997).
A complete overview of the original mission, written before the loss with Ariane-5, was given in a series of articles in ESA Bulletin no. 84 (November 1995).
ESA SP-1159, Paris, March 1993 is entitled "Cluster: Mission, Payload and Supporting Activities."
Information about the Cluster 2/FM5 (Rumba) mission
| Role | Person | |
|---|---|---|
| 1. | Project scientist | Dr. Melvyn L. Goldstein |
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The four similar spacecraft of the Cluster II mission are part of ESA's and NASA's Solar-Terrestrial Science Program (STSP). The current Cluster II mission is a near-replica of the original four-spacecraft mission lost at launch in 1996. (NSSDC will carry the name "Cluster96" in its information files to designate the unsuccessful 1996 four-spacecraft Ariane 5 launch.) The purpose of the Cluster II mission is to study small-scale structures in three dimensions in the Earth's plasma environment, such as those involved in the interaction between the solar wind and the magnetospheric plasma, in global magnetotail dynamics, in cross-tail currents, and in the formation and dynamics of the neutral line and of plasmoids.
| Role | Person | |
|---|---|---|
| 1. | Project scientist | Dr. Melvyn L. Goldstein |
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Coordinated Data Analysis Web (CDAWeb) supports not only interactive plotting of variables from multiple instruments on multiple investigations simultaneously on arbitrary, user-defined time-scales. It also supports data retrieval in various formats using its interactive web interface or ftp service.
Coordinated Data Analysis Web (CDAWeb) home page at Space Physics Data Facility of the NASA Goddard Space Flight Center.
| Role | Person | |
|---|---|---|
| 1. | Project scientist | Dr. Robert E. McGuire |
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The Cluster Active Archive is a depository of processed and validated high-resolution Cluster data, raw data, processing software, calibration data, documentation and other value added products.
For presentations and publications, please acknowledge the instrument teams and the Cluster Active Archive.
| Role | Person | |
|---|---|---|
| 1. | General contact | Dr. Harri Laakso |
| 2. | Technical contact | Dr. Christopher H. Perry |
Access to the CAA is restricted and requires registration.