Data Set Overview : THIS DATA SET CONTAINS THE ION PARAMETERS IN THE PLS VOLTAGE RANGE (10-5950 EV/Q) WITH FORMAL 1 SIGMA ERRORS OBTAINED FROM VOYAGER 2 DATA AT SATURN BY FITTING THE MEASURED SPECTRA WITH ISOTROPIC MAXWELLIAN DISTRIBUTIONS TO OBTAIN PLASMA DENSITIES, TEMPERATURES, AND VELOCITY. ONLY SPECTRA WHICH HAD DISTINCT CURRENT PEAKS WERE FIT. SPECTRA WERE FIT USING ONE OR TWO ION SPECIES, PROTONS AND/OR A HEAVY ION WHICH WAS TAKEN TO BE NITROGEN OUTSIDE OF 14 RS AND OXYGEN ELSEWHERE. OUTSIDE L:10-12 ION SPECTRA CHANGE RAPIDLY, SO THE VALUES IN THIS DATA SET DO NOT REPRESENT AVERAGE PLASMA CONDITIONS IN THE OUTER MAGNETOSPHERE. THE VALUES FOR POSITION AND MAGNETIC FIELD GIVEN IN THE DATA SET ARE ONLY APPROXIMATE AND SHOULD NOT BE USED FOR PUBLICATION. PARAMETERS WHICH ARE IDENTICALLY 0 AND HAVE UNCERTAINTIES OF 0 WERE NOT FIT DUE TO INSUFFICIENT DATA; THESE NUMBERS ARE THUS NOT REAL VALUES. A COMPLETE DESCRIPTION OF THIS DATA SET IS GIVEN IN RICHARDSON (1986). DATA FORMAT: EACH DATA RECORD CONSISTS OF 5+2N LINES, WHERE N IS THE NUMBER OF IONS FIT. LINE 1: S (A1, INDICATES THE START OF A NEW FIT); TIME OF SPECTRUM; YR(I4),DY(I3), HRMIN(I5),SEC.MSEC(F7.3); SPACECRAFT LOCATION; RADIUS(F7.3),RHO(F7.3); MAGNETIC FIELD; BRHO,BPHI,BZ(3F7.3); MODE; L OR M(I2); DATE FIT WAS DONE; MONTHDAYYEAR(I7); INITIALS OF FITTER(I4); NUMBER OF ANALYSIS ROUTINE USED; (EQUALS 4 IN THIS DATA SET, INDICATING PROGRAMS INCORPORATING THE FULL RESPONSE FUNCTION OF THE INSTRUMENT FOR L MODES DATA): CHI-SQUARE FROM FIT (E7.3);NUMBER OF IONS FIT (I2): LINES 2-5 TELL WHICH CHANNELS WERE FIT: CUP IDENTIFIER (A,B,C,D) (A1); NUMBER OF SETS OF CHANNELS FIT (I3); BEGINNING AND ENDING CHANNEL OF EACH SET (2-20I3): LINE 6; FIT PARAMETERS FOR IONS: F (LINE IDENTIFIER) (A1); ION SPECIES NUMBER (1-8) (I1)ION MASS, CHARGE (I3,I2); DEN,XDEN,VR,XVR,VPHI,XVPHI (6E10.3), WHERE THE X* VARIABLES ARE FORMAL 1 SIGMA UNCERTAINTIES: LINE 7; REMAINING FIT PARAMETERS: G (LINE IDENTIFIER), ION SPECIES NUMBER (A1, I1); VZ,XVZ,WPAR,XWPAR,WPER, XWPER (6E10.3). LINES 6 AND 7 REPEAT ONCE FOR EACH ION SPECIES. A CYLINDRICAL COORDINATE SYSTEM CENTERED ON THE PLANET IS USED, WITH RHO OUTWARDS FROM THE SPIN AXIS, PHI IN THE DIRECTION OF ROTATION, AND Z THE DISTANCE ABOVE THE EQUATOR. V'S ARE VELOCITIES IN KM/S, W'S THERMAL SPEEDS IN KM/S, AND DEN'S DENSITIESIN CM-3. VALUES OF B AND POSITION INFORMATION MAY BE UNRELIABLE AND SHOULD BE VERIFIED BEFORE USE. 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 RICHARDSON (1986) 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 VECTOR MOMENTUM FRAME OR VELOCITY FRAME TO WHICH ONE MUST TRANSFORM IN A derived parameter equaling the number of ions per unit ION THERMAL SPEED: A measure of the velocity associated with ORDER TO YIELD ION ANGULAR DISTRIBUTIONS AND-OR the temperature of the ions. It is formally defined as the volume over a specified range of ion energy, energy/charge, ELECTRON ANGULAR DISTRIBUTIONS THAT ARE ANGULARLY Ion Thermal Speed squared equals two times K (Boltzmann's or energy/nucleon. Discrimination with regard to mass and or ISOTROPIC AT ALL ENERGIES. SUCH A FRAME CAN BE constant) times T (temperature of ion) divided by M (ion charge state is necessary to obtain this quantity, however, FOUND ONLY IF OTHER EFFECTS THAT CAN YIELD ANGULAR mass). Each component of a plasma has a thermal speed mass and charge state are often assumed due to instrument limitations. associated with it. ANISOTROPIES (E.G. SPATIAL GRADIENTS) ARE  FACTORED OUT. THE COMPONENT OF THE TRANSFORM VELOCITY VECTOR PERPENDICULAR TO THE LOCAL Many different forms of ion density are derived. Some are MAGNETIC FIELD VECTOR IS COUPLED TO THE distinguished by their composition (N+, proton, ion, etc.) APPROXIMATELY TIME STATIONARY ELECTRIC FIELD. or their method of derivation (Maxwellian fit, method of PARALLEL TO THE LOCAL MAGNETIC FIELD VECTOR A FLOW moments). In some cases, more than one type of density will VELOCITY FRAME MAY OR MAY NOT BE A WELL DEFINED be provided in a single dataset. In general, if more than QUANTITY. 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 THERMAL SPEED Instrument Parameter Name : ION RATE Important Instrument Parameters : 1  Instrument Host ID : VG2 Data Set Parameter Name : ION THERMAL SPEED 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 : MJSANL Product Data Set ID : VG2-S-PLS-5-ION-FIT-96.0SEC   Software 'MJSANL' ----------------- Software Name : MJSANL 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 ION PARAMETERS IN THE PLS ENERGY RANGE (10-5950 EV). FORMAL 1 SIGMA UNCERTAINTIES FOR THE DERIVED VELOCITIES, DENSITIES, AND THERMAL SPEEDS AND RANGE FROM A FEW TO 100%. SYSTEMATIC ERRORS MAY RESULT FROM THE USE OF ISOTROPIC MAXWELLIAN DISTRIBUTIONS TO MODEL THE IONS, WHICH RESULTS IN AN UNDERESTIMATE OF THE TOTAL ION DENSITY AND ION THERMAL SPEED OF LESS THAN 20%, BUT HAS LITTLE EFFECT (FEW PERCENT) ON THE VELOCITY DETERMINATION. POSITION AND MAGNETIC FIELD DATA IN THIS DATA SET ARE ONLY APPROXIMATE AND SHOULD NOT BE RELIED UPON. ONLY SPECTRA WITH AT LEAST ONE CURRENT PEAK WERE FIT; THIS GIVES A BIASED SELECTION OF THE DATA, PARTICULARLY OUTSIDE L:10 WHERE THE DATA GIVEN IS NOT REPRESENTATIVE OF 'AVERAGE' PLASMA CONDITIONS. SEE RICHARDSON (1986) FOR DETAILS.