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VOYAGER 1 SATURN PLASMA DERIVED ELECTRON PARAMETERS 96 SEC (PDS)

NSSDCA ID: PSFP-00520

Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1980-11-12 to 1980-11-13

Description

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

Data Set Overview ================= THIS DATA SET CONTAINS ELECTRON PARAMETERS IN THE PLS ENERGY RANGE (10-5950 EV) AT SATURN DURING THE VOYAGER 1 ENCOUNTER. PARAMETERS ARE CALCULATED IN SEVERAL WAYS. TOTAL MOMENT DENSITY AND TEMPERATURE ARE GIVEN. EACH ELECTRON SPECTRUM IS ALSO FIT WITH A THERMAL COMPONENT AND 1-3 HOT COMPONENTS DEPENDING ON HOW MANY MAXWELLIANS ARE NEEDED TO FIT THE ENTIRE DISTRIBUTION. THE MOMENT DENSITY AND TEMPERATURE OF THE HOT COMPONENT IS CALCULATED AFTER THE THERMAL COMPONENT IS SUBTRACTED FROM THE SPECTRUM. THE CHI-SQUARE VALUE FOR EACH FIT IS GIVEN. THE SPACECRAFT CHARGE IS NOT CALCULATED CONSISTENTLY, AND MAY RESULT IN FACTOR OF 2-3 ERRORS IN THE THERMAL ELECTRON DENSITY. DATA IS UNRELIABLE INSIDE 6 RS AND IN THE OCCULTATION REGIONS. A COMPLETE DESCRIPTION OF THIS DATA SET IS IN SITTLERETAL. (1983). FITTING PARAMETERS ARE DESCRIBED AS BELOW: =============================================================== name type description --------------------------------------------------------------time A24 time in the format yyyy-mm-ddThh:mm:ss.sssZ imax I2 points in spectrum ifly I1 flag value: 1 = encounter, 0 = cruise thbn 1PE9.3 angle between d cup normal and mag. field vector (radians) rne 1PE9.3 moment electron density (cnts/cm**3) rte 1PE9.3 moment electron temperature (eV) phisc 1PE9.3 spacecraft potential (V) rnc 1PE9.3 cold electron density (cnts/cm**3) sgnc 1PE9.3 std. dev. of cold electron density (rnc) (cnts/cm**3) rtc 1PE9.3 cold electron temperature (eV) sgtc 1PE9.3 std. dev. of cold electron temperature (rtc) (eV) chic 1PE9.3 chi squared of the cold fit rnh1 1PE9.3 first hot electron density (cnts/cm**3) sgnh1 1PE9.3 std. dev. of first hot electron dens. (rnh1) (cnts/cm**3) th1 1PE9.3 first hot electron temperature (eV) sgth1 1PE9.3 std. dev. of first hot electron temp. (th1) (eV) chih1 1PE9.3 chi squared of the first hot fit rnh2 1PE9.3 second hot electron density (cnts/cm**3) sgnh2 1PE9.3 std. dev. of second hot electron dens. (rnh2) (cnts/cm**3) th2 1PE9.3 second hot electron temperature (eV) sgth2 1PE9.3 std. dev. of second hot electron temp. (th2) (eV) chih2 1PE9.3 chi squared of second hot fit rnh3 1PE9.3 third hot electron density (cnts/cm**3) sgnh3 1PE9.3 std. dev. of third hot electron dens. (rnh3) (cnts/cm**3) th3 1PE9.3 third hot electron temperature (eV) sgth3 1PE9.3 std. dev. of third hot electron temp. (th1) (eV) chih3 1PE9.3 chi squared of third hot fit chi 1PE9.3 chi squared for total fit rnh 1PE9.3 moment of the hot electron density (cnts/cm**3) rth 1PE9.3 moment of the hot electron temperature (eV) IN COMPUTING RNH1 AND TH1 WE USED THE 3RD TO 7TH CHANNELS ABOVE THE BREAKPOINT ENERGY EB1 AND SUBTRACTED THE COLD COMPONENT FC FROM FE (OBSERVED) BEFORE DOING THE FIT. IN REALITY THIS FIT WAS DONE ITERATIVELY BETWEEN THE COLD AND HOT COMPONENT FITS (FC=FE-FH AND FH=FE-FC ETC.). A SIMILAR APPROACH WAS USED IN COMPUTING RNH3,TH3 FOR WHICH A MAXWELLIAN FIT WAS DONE TO THOSE CHANNELS ABOVE EB2. THE PARAMETERS RNH2,TH2 WERE FIT TO THE UPPER 5 (3 MIN) CHANNELS (GENERALLY ABOVE EB2). THIS FIT WAS PRIMARILY DONE TO ALLOW PROPER ESTIMATION OF FE TO THE HIGH ENERGY PORTION OF THE SPECTRUM. IN MANY CASES THERE ARE NOT SUFFICIENT POINTS TO COMPUTE RNH3,TH3 AND RNH2,TH2 DO PROVIDE A FAIR REPRESENTATION OF THE SPECTRUM. IF RNH1=RNH2=RNH3 THEN YOU SHOULD NOT USE THE 2ND AND 3RD FIT PARAMETERS. 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 SITTLER ET AL. (1983) 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 : ELECTRON 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 giving an indication of the mean A derived parameter equaling the number of electrons per unit volume over a specified range of electron energy. energy/electron, assuming the shape of the electron energy Different forms of electron density are derived spectrum to be Maxwellian (i.e. highest entropy shape). Given distinguished by method of derivation (Maxwellian fit, that the electron energy spectrum is not exactly Maxwellian, method of moments) or by the some selection criteria (ie., the electron temperature can be defined integrally (whereby the mean energy obtained by integrating under the actual hot electron and cold electron density). In general, if more electron energy spectrum is set equal to the integral under than one electron component is analyzed, either by moment or fit, a total density will be provided which is the sum of a Maxwellian, where the temperature is a free parameter for the electron densities. If the electron do not have a which to solve), or differentially (whereby the slopes of Maxwellian distribution the actual distribution can be the actually electron energy spectrum at various energies are matched to the slopes of a corresponding Maxwellian). represented as the sum of several Maxwellians, in which case the density of each Maxwellian is given. The temperature parameter is often qualified with a range of applicable energies. temperatures can be angularly anisotropic. If the electrons do not have a Maxwellian distribution the actual distribution can be represented as the sum of several Maxwellians, each with a separate temperature. Source Instrument Parameters ============================ Instrument Host ID : VG1 Data Set Parameter Name : ELECTRON DENSITY Instrument Parameter Name : ELECTRON RATE Important Instrument Parameters : 1 Instrument Host ID : VG1 Data Set Parameter Name : ELECTRON DENSITY Instrument Parameter Name : ELECTRON CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG1 Data Set Parameter Name : ELECTRON TEMPERATURE Instrument Parameter Name : ELECTRON RATE Important Instrument Parameters : 1 Instrument Host ID : VG1 Data Set Parameter Name : ELECTRON TEMPERATURE Instrument Parameter Name : ELECTRON CURRENT Important Instrument Parameters : 1 Processing ========== Processing History -----------------Source Data Set ID : VG1-PLS Software : UNK Product Data Set ID : VG1-S-PLS-5-ELE-PAR-96.0SEC

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

https://pds-ppi.igpp.ucla.edu/data/VG1-S-PLS-5-SUMM-ELE-FIT-96SEC-V1.0/

Alternate Names

  • VG1-S-PLS-5-SUMM-ELE-FIT-96SEC-V1.0

Discipline

  • Planetary Science: Fields and Particles

Additional Information

Spacecraft

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

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. John D. RichardsonGeneral ContactMassachusetts Institute of Technologyjdr@space.mit.edu
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