Data Set Information
DATA_SET_NAME VOYAGER 1 JUP PLASMA SPECTROMETER EDITED SPEC 4.0SEC
DATA_SET_ID VG1-J-PWS-2-SA-4.0SEC
NSSDC_DATA_SET_ID 77-084A-13C
DATA_SET_TERSE_DESCRIPTION VOYAGER 1 JUP PLASMA SPECTROMETER EDITED SPEC 4.0SEC
DATA_SET_DESCRIPTION
Data Set Overview
    =================
      This data set consists of 4-second edited, wave electric field
      intensities from the Voyager 1 Plasma Wave Receiver spectrum
      analyzer obtained in the vicinity of the Jovian magnetosphere.
      For each 4-second interval, a field strength is determined for
      each of the 16 spectrum analyzer channels whose center
      frequencies range from 10 Hertz to 56.2 kiloHertz and which are
      logarithmically spaced in frequency, four channels per decade.
      The time associated with each set of intensities (16 channels)
      is the time of the beginning of the scan.  During data gaps
      where complete 4-second spectra are missing, no entries exist
      in the file, that is, the gaps are not zero-filled or tagged in
      any other way.  When one or more channels are missing within a
      scan, the missing measurements are zero-filled.  Data are
      edited but not calibrated.  The data numbers in this data set
      can be plotted in raw form for event searches and simple trend
      analysis since they are roughly proportional to the log of the
      electric field strength.  Calibration procedures and tables are
      provided for use with this data set; the use of these is
      described below.
 
      Use of Voyager PWS Calibration Tables
 
      The Voyager PWS calibration tables are given in two plain ASCII
      text files named VG1PWSCL.TAB and VG2PWSCL.TAB (for Voyagers-1
      and -2, respectively).  These provide information to convert
      the uncalibrated `data number' output of the PWS 16-channel
      spectrum analyzer to calibrated antenna voltages for each
      frequency channel.  Following is a brief description of these
      files and a tutorial in their application.
 
      The first column lists an uncalibrated data number followed by
      the corresponding value in calibrated volts for each of the 16
      frequency channels of the PWS spectrum analyzer.  Each line
      contains calibrations for successive data number values ranging
      from 0 through 255.  (Data number 0 actually represents the
      lack of data since the baseline noise values for each channel
      are all above that.)
 
 
      A data analysis program may load the appropriate table into a
      data structure and thus provide a simple look-up scheme to
      obtain the appropriate voltage for a given data number and
      frequency channel.  For example, the following VAX FORTRAN code
      may be used to load a calibration array for Voyager 1 PWS:
 
      real*4 cal (16,0:255)
      open ( unit=10, file='vg1pwscl.tab',status='old')
      do i=0,38
         read (10,*) ! skip 38 lines of label info
      end do
      do i=0,255
         read (10,*) idn,(cal(ichan,i),ichan=1,16)
      end do
      close (10)
 
 
      Then, given an uncalibrated data value idn for the frequency
      channel ichan, the corresponding calibrated antenna voltage
      would be given by the following array reference:
 
      volts = cal (ichan, idn)
 
 
      This may be converted to a wave electric field amplitude by
      dividing by the effective antenna length in meters, 7.07m.
      That is:
 
      efield = cal(ichan, idn) / 7.07
 
 
      Spectral density units may be obtained by dividing the square
      of the electric field value by the nominal frequency bandwidth
      of the corresponding spectrum analyzer channel.
 
      specdens = (cal(ichan,idn)/7.07)**2 / bandwidth(ichan)
 
 
      Finally, power flux may be obtained by dividing the spectral
      density by the impedance of free space in ohms:
 
 
    pwrflux = ((cal(ichan,idn)/7.07)**2/bandwidth(ichan)) / 376.73
 
 
      Of course, for a particular application, it may be more
      efficient to apply the above conversions to the calibration
      table directly.
 
      The center frequencies and bandwidths of each PWS spectrum
      analyzer channel for each Voyager 1 PWS are given below:
 
      VOYAGER 1 PWS SPECTRUM ANALYZER
 
 
      Voyager-1 Channel Center Frequency Bandwidth
 
      1 10.0 Hz 2.99 Hz 2 17.8 Hz 3.77 Hz 3 31.1 Hz 7.50 Hz 4 56.2 Hz
      10.06 Hz 5 100.  Hz 13.3 Hz 6 178.  Hz 29.8 Hz 7 311.  Hz 59.5
      Hz 8 562.  Hz 106.  Hz 9 1.00 kHz 133.  Hz 10 1.78 kHz 211.  Hz
      11 3.11 kHz 298.  Hz 12 5.62 kHz 421.  Hz 13 10.0 kHz 943.  Hz
      14 17.8 kHz 2110.  Hz 15 31.1 kHz 4210.  Hz 16 56.2 kHz 5950.
      Hz
 
 
      Additional information about this dataset and the instrument
      which produced it can be found elsewhere in this catalog.  An
      overview of the data in this data set can be found in Scarf et
      al.  [1979] and a complete instrument description can be found
      in Scarf and Gurnett [1977].
 
 
      Processing Level Id            : 2
      Software Flag                  : Y
      Processing Start Time          : 1988-02-01
 
 
    Parameters
    ==========
      Sampling Parameter Name        : TIME
      Data Set Parameter Name        : PLASMA WAVE SPECTRUM
      Sampling Parameter Resolution  : 4.000000
      Minimum Sampling Parameter     : 197709051420.000000
      Sampling Parameter Interval    : 4.000000
      Minimum Available Sampling Int : 4.000000
      Data Set Parameter Unit        : VOLT/METER
      Noise Level                    : 0.000005
      Sampling Parameter Unit        : SECOND
 
 
      Description
      -----------
        A set of derived parameters consisting of wave electric field
        intensities or electric field spectral densities at various
        contiguous frequencies over a range of frequencies.  The MKS
        units are: Volts/Meter or Volts**2/(Hertz.Meter**2),
        respectively.
 
 
    Source Instrument Parameters
    ============================
      Instrument Host ID              : VG1
      Data Set Parameter Name         : PLASMA WAVE SPECTRUM
      Instrument Parameter Name       : ELECTRIC FIELD WAVEFORM
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG1
      Data Set Parameter Name         : PLASMA WAVE SPECTRUM
      Instrument Parameter Name       : ELECTRIC FIELD COMPONENT
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG1
      Data Set Parameter Name         : PLASMA WAVE SPECTRUM
      Instrument Parameter Name       : MAGNETIC FIELD COMPONENT
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG1
      Data Set Parameter Name         : PLASMA WAVE SPECTRUM
      Instrument Parameter Name       : WAVE ELECTRIC FIELD INTENSITY
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG1
      Data Set Parameter Name         : PLASMA WAVE SPECTRUM
      Instrument Parameter Name       : WAVE MAGNETIC FIELD INTENSITY
      Important Instrument Parameters : 1
 
 
    Processing
    ==========
 
      Processing History
      ------------------
        Source Data Set ID          : N/A
        Software                    : UNK
        Product Data Set ID         : VG1-J-PWS-2-SA-4.0SEC
 
        Source Data Set ID          : VG1-J-PWS-2-SMSF
        Software                    : CDMAKE
        Product Data Set ID         : VG1-J-PWS-2-SA-4.0SEC
 
 
      Software 'CDMAKE'
      -----------------
          CDMAKE is primarily a data format translation routine which
          is used to convert Voyager Plasma Wave Spectrometer (PWS)
          MSF tape files to CD files. The MSF, or Master Science
          Files, are produced at the University of Iowa as the
          primary, ordered, full-information PWS spectrum analyzer
          data set. The CD files contain uncalibrated, full-resolution
          PWS data with minimal ancillary data in a simplified format
          which may be used in CDROM production.
 
          Note: SOFTWARE IS NOT AVAILABLE FOR PUBLIC USE.
 
        Software Name               : CDMAKE
        Software Type               : N/A
        Software Release Date       : 1988-08-01
        Node ID                     : PPI-IOWA
        Cognizant Engineer          : MR. LARRY J. GRANROTH
        Software Access Description : N/A
DATA_SET_RELEASE_DATE 1988-08-01T00:00:00.000Z
START_TIME 1979-02-28T12:00:00.000Z
STOP_TIME 1979-03-23T12:00:00.000Z
MISSION_NAME VOYAGER
MISSION_START_DATE 1972-07-01T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME JUPITER
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID VG1
INSTRUMENT_NAME PLASMA WAVE RECEIVER
INSTRUMENT_ID PWS
INSTRUMENT_TYPE PLASMA WAVE SPECTROMETER
NODE_NAME Planetary Plasma Interactions
ARCHIVE_STATUS SUPERSEDED
CONFIDENCE_LEVEL_NOTE
Overview
    ========
      This data set includes all available spectrum analyzer data
      within the interval of time covered.  The data set has been
      cleaned as well as possible for periodic noise spikes due to a
      stepper motor operating on the LECP and a modulated grid within
      the PLS.  The 'bad' points remain in the data set as negative
      numbers with the same absolute value as the original data point
      so that the point can be skipped in normal data processing by
      testing for negative values or recovered for special inpection
      by converting the sign back to a positive one.  Other possible
      sources of noise which have not been eliminated include random
      intense spikes of noise below 1 kiloHertz due to the operation
      of attitude control thrusters.  Other randomly occurring spikes
      or time periods of intense spikes over the entire frequency
      range are indicative of telemetry errors.  No attempt has been
      made to remove spikes since some could be valid data, i.e.
      real bursts of wave activity.  The 17.8-Hz channel is sometimes
      contaminated by interference from the PRA instrument, depending
      on that instrument's mode.  This interference is at a
      relatively constant level.
CITATION_DESCRIPTION Citation TBD
ABSTRACT_TEXT This data set consists of 4-second edited, wave electric field intensities from the Voyager 1 Plasma Wave Receiver spectrum analyzer obtained in the vicinity of the Jovian magnetosphere. For each 4-second interval, a field strength is determined for each of the 16 spectrum analyzer channels whose center frequencies range from 10 Hertz to 56.2 kiloHertz and which are logarithmically spaced in frequency, four channels per decade. The time associated with each set of intensities (16 channels) is the time of the beginning of the scan. During data gaps where complete 4-second spectra are missing, no entries exist in the file, that is, the gaps are not zero-filled or tagged in any other way. When one or more channels are missing within a scan, the missing measurements are zero-filled. Data are edited but not calibrated. The data numbers in this data set can be plotted in raw form for event searches and simple trend analysis since they are roughly proportional to the log of the electric field strength. Calibration procedures and tables are provided for use with this data set described below.
PRODUCER_FULL_NAME DR. WILLIAM S. KURTH
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