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Availability: Archived at NSSDC, accessible from elsewhere


This description was generated automatically using input from the Planetary Data System.

Data Set Overview ================= Version 1.1 ----------This version 1.1 data set replaces the version 1.0 data set (DATA_SET_ID = VG1-J-PLS-5-ION-MOM-96.0SEC) previously archived with the PDS. Data Set Description -------------------This data set contains the best estimates of the total ion density at Jupiter during the Voyager 1 encounter in the PLS voltage range (10-5950 eV/Q). It is calculated using the method of [MCNUTTETAL1981] 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 before 1979 63 1300, after this the larger of the high and low resolution mode densities in a 96 sec period is used since the L-mode spectra often are saturated. 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 [MCNUTTETAL1981] 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: column 1 is time (yyyy-mm-ddThh:mm:ss.sssZ), column 2 is the moment density in cm^-3. Each row has format (a24, 1x, 1pe9.2). Values of -9.99e+10 indicate that the parameter could not be obtained from the data using the standard analysis technique. Additional information about this data set 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 [MCNUTTETAL1981] and a complete instrument description can be found in [BRIDGEETAL1977]. Processing Level Id : 5 Software Flag : Y Parameters ========== Ion Density ----------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 : EV Sampling Parameter Unit : SECOND 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 data set. 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 : VG1 Data Set Parameter Name : ION DENSITY Instrument Parameter Name : ION RATE ION CURRENT PARTICLE MULTIPLE PARAMETERS Important Instrument Parameters : 1 (for all parameters) Processing ========== Processing History -----------------Source Data Set ID : VG1-PLS Software : MOMANAL Product Data Set ID : VG1-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 Data Coverage ============= Filename Records Start Stop ------------------------------------------------------------------T790301 3792 1979-03-01T12:04:12.474Z 1979-03-05T16:45:54.608Z

These data are available on-line from the Planetary Data System (PDS) at:

Alternate Names

  • VG1-J-PLS-5-SUMM-ION-MOM-96.0SEC-V1.1


  • Planetary Science: Fields and Particles

Additional Information


Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Dr. John D. RichardsonGeneral ContactMassachusetts Institute of
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