Data Set Overview
    =================
      THIS DATA SET CONTAINS THE BEST ESTIMATES OF THE TOTAL ION
      DENSITY FROM VOYAGER 2 AT JUPITER IN THE PLS VOLTAGE RANGE
      (10-5950 EV/Q).  IT IS CALCULATED USING THE METHOD OF MCNUTT ET
      AL.  (1981) WHICH TO FIRST ORDER CONSISTS OF TAKING THE TOTAL
      MEASURED CURRENT AND DIVIDING BY THE COLLECTOR AREA AND PLASMA
      BULK VELOCITY.  THIS METHOD IS ONLY ACCURATE FOR HIGH MACH
      NUMBER FLOWS DIRECTLY INTO THE DETECTOR, AND MAY RESULT IN
      UNDERESTIMATES OF THE TOTAL DENSITY OF A FACTOR OF 2 IN THE
      OUTER MAGNETOSPHERE.  THUS ABSOLUTE DENSITIES SHOULD BE TREATED
      WITH CAUTION, BUT DENSITY VARIATIONS IN THE DATA SET CAN BE
      TRUSTED.  THE LOW RESOLUTION MODE DENSITY IS USED AT ALL TIMES
      EXCEPT DAY 190 2100-2200 WHEN THE LARGER OF THE HIGH AND LOW
      RESOLUTION MODE DENSITIES IN A 96 SEC PERIOD IS USED.
      COROTATION IS ASSUMED INSIDE L=17.5, AND A CONSTANT VELOCITY
      COMPONENT OF 200 KM/S INTO THE D CUP IS USED OUTSIDE OF THIS.
      THESE ARE THE DENSITIES GIVEN IN THE MCNUTT ET AL.  (1981)
      PAPER CORRECTED BY A FACTOR OF 1.209 (.9617) FOR DENSITIES
      OBTAINED FROM THE SIDE (MAIN) SENSOR.  THIS CORRECTION IS DUE
      TO A BETTER CALCULATION OF THE EFFECTIVE AREA OF THE SENSORS.
      DATA FORMAT: COLUMNS 1-6 ARE TIME (YEAR, DAY, HOUR, MIN, SEC,
      MSEC) COLUMN 7 IS THE MOMENT DENSITY IN CM-3.  EACH ROW HAS
      FORMAT (6I4, E12.3).  VALUES OF 1.E32 INDICATE THAT THE
      PARAMETER COULD NOT BE OBTAINED FROM THE DATA USING THE
      STANDARD ANALYSIS TECHNIQUE.  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 MCNUTT ET AL.  (1981) AND A COMPLETE
      INSTRUMENT DESCRIPTION CAN BE FOUND IN BRIDGE (1977).
 
 
      Processing Level Id            : 5
      Software Flag                  : Y
 
 
    Parameters
    ==========
      Sampling Parameter Name        : TIME
      Data Set Parameter Name        : ION DENSITY
      Sampling Parameter Resolution  : 96.000000
      Sampling Parameter Interval    : 96.000000
      Minimum Available Sampling Int : 96.000000
      Data Set Parameter Unit        : CM-3
      Sampling Parameter Unit        : SECOND
 
 
      Description
      -----------
        A derived parameter equaling the number of ions per unit
        volume over a specified range of ion energy, energy/charge,
        or energy/nucleon.  Discrimination with regard to mass and or
        charge state is necessary to obtain this quantity, however,
        mass and charge state are often assumed due to instrument
        limitations.
 
        Many different forms of ion density are derived.  Some are
        distinguished by their composition (N+, proton, ion, etc.) or
        their method of derivation (Maxwellian fit, method of
        moments).  In some cases, more than one type of density will
        be provided in a single dataset.  In general, if more than
        one ion species is analyzed, either by moment or fit, a total
        density will be provided which is the sum of the ion
        densities.  If a plasma component does not have a Maxwellian
        distribution the actual distribution can be represented as
        the sum of several Maxwellians, in which case the density of
        each Maxwellian is given.
 
 
    Source Instrument Parameters
    ============================
      Instrument Host ID              : VG2
      Data Set Parameter Name         : ION DENSITY
      Instrument Parameter Name       : ION RATE
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG2
      Data Set Parameter Name         : ION DENSITY
      Instrument Parameter Name       : ION CURRENT
      Important Instrument Parameters : 1
 
      Instrument Host ID              : VG2
      Data Set Parameter Name         : ION DENSITY
      Instrument Parameter Name       : PARTICLE MULTIPLE PARAMETERS
      Important Instrument Parameters : 1
 
 
    Processing
    ==========
 
      Processing History
      ------------------
        Source Data Set ID          : VG2-PLS
        Software                    : MOMANAL
        Product Data Set ID         : VG2-J-PLS-5-ION-MOM-96.0SEC
 
 
      Software 'MOMANAL'
      ------------------
        Software Name               : MOMANAL
        Software Type               : PIN
        Software Release Date       : N/A
        Node ID                     : N/A
        Cognizant Engineer          : N/A
        Software Access Description : N/A

Overview
    ========
      THIS DATA SET PROVIDES AN ESTIMATE OF THE POSITIVE ION CHARGE
      DENSITY.  SEVERAL ASSUMPTION/SIMPLIFICATIONS ARE MADE TO
      SIMPLIFY THE ANALYSIS WHICH MAY AFFECT THE ACCURACY OF THE
      RESULTS.  HIGH MACH NUMBER FLOW IS ASSUMED; MACH NUMBERS OF
      2-3, WHICH ARE REASONABLE LOWER LIMITS FOR HEAVY IONS, RESULT
      IN 10-20% UNDERESTIMATES OF THE CHARGE DENSITY.  THE ANALYSIS
      ASSUMES A UNIT RESPONSE (IE., ALL PARTICLES IN A COLD BEAM
      INCIDENT ON THE APERTURE OF THE EXPERIMENT WOULD BE MEASURED AT
      THE COLLECTOR).  THE ACTUAL RESPONSE IS DOCUMENTED IN MCNUTT ET
      AL.  (1981) AND CAN BE AS LOW AS 70%.  A VELOCITY INTO THE
      DETECTOR MUST ALSO BE ASSUMED; THE VELOCITY USED IS THE
      COROTATION VELOCITY INSIDE OF 17.5 RJ AND 200 KM/S OUTSIDE OF
      THIS.  THIS VELOCITY PROFILE IS IN ACCORD WITH THAT MEASURED
      WHERE VELOCITY DETERMINATIONS ARE POSSIBLE, BUT THE USE OF
      INCORRECT VALUES GIVE ERRORS IN THE DENSITY WHICH VARY LINEARLY
      WITH ERRORS IN THE VELOCITY.  FINALLY, ONLY IONS IN THE PLS
      ENERGY RANGE (10-5950 EV/Q) ARE COUNTED.  THE CUMULATIVE ERROR
      FROM ALL THESE EFFECTS IS LESS THAN 10% IN THE SOLAR WIND, LESS
      THAN A FACTOR OF TWO IN THE OUTER MAGNETOSPHERE (R>20 RJ) AND
      LESS THAN 20-30% INSIDE OF THIS.  SINCE THE AMPLITUDE OF EACH
      OF THESE EFFECTS VARIES SLOWLY IN TIME (DISTANCE), THE RELATIVE
      CHANGES IN DENSITY ARE GOOD TO A FEW PERCENT IN MOST CASES.