PDS3_DATA_SET_ID = VG1-S-PLS-5-SUMM-ELEFBR-96SEC-V1.0 DATA_SET_NAME = VOYAGER 1 SATURN PLASMA DERIVED ELECTRON BROWSE 96 SEC START_TIME = 1980-11-12T00:00:30.505 STOP_TIME = 1980-11-13T18:30:54.537 ORIGINAL_DATA_SET_RELEASE_DATE = 2002-10-14 PRODUCER_FULL_NAME = JOHN D. RICHARDSON CITATION_DESC = Richardson, J.D., VG1-S-PLS-5-SUMM-ELEFBR-96SEC-V1.0, VOYAGER 1 SATURN PLASMA DERIVED ELECTRON BROWSE 96 SEC, NASA Planetary Data System, 2002. REFERENCES: Bridge, H.S., J.W. Belcher, R.J. Butler, A.J. Lazarus, A.M. Mavretic, J.D. Sullivan, G.L. Siscoe, and V.M. Vasyliunas, The Plasma Experiment on the 1977 Voyager Mission, Space Sci. Rev., Vol. 21, p. 259, 1977. Bridge, H.S., J.W. Belcher, A.J. Lazarus, S. Olbert, J.D. Sullivan, F. Bagenal, P.R. Gazis, R.E. Hartle, K.W. Ogilvie, J.D. Scudder, E.C. Sittler, A. Eviatar, G.L. Siscoe, C.K. Goertz and V.M. Vasyliunas, Plasma Observations Near Saturn: Initial resullts for Voyager 1, Science, Vol 212, p. 217, 1981. Sittler, E.C., Jr., K.W. Ogilvie, and J.D. Scudder, survey of low-energy plasma electrons in Saturn's Magnetosphere, J. Geophys. Res., 88, 8848-8870, 1983. DATA_SET_DESCRIPTION Data Set Overview ================= THIS DATA SET CONTAINS THE THERMAL ELECTRON DENSITY AND TEMPERATURE IN THE PLS ENERGY RANGE (10-5950 EV) FROM VOYAGER 1 AT SATURN DERIVED BY FITTING THE LOW ENERGY ELECTRON COMPONENT WITH A MAXWELLIAN DISTRIBUTION, AND THE MOMENT DENSITY AND TEMPERATURE OF THE HOT ELECTRONS CALCULATED AFTER THE SIGNAL FROM THE THERMAL COMPONENT IS SUBTRACTED FROM THE ELECTRON SPECTRA. IT IS A SUBSET OF THE DATA SET VG1-S-PLS-5-SUMM-ELE-FIT-96SEC-V1.0 WHICH SHOULD BE OBTAINED BEFORE THIS DATA IS USED. SPACECRAFT CHARGING MAY RESULT IN FACTOR OF 2-3 ERRORS IN THE THERMAL ELECTRON DENSITY. DATA FORMATS ARE DESCRIBED AS BELOW: =================================================================== name type description ------------------------------------------------------------------- time A24 time in the format yyyy-mm-ddThh:mm:ss.sssZ fit_den 1PE10.3 fit density of thermal electron component (cnts/cm**3) fit_temp 1PE10.3 fit temperature of thermal electron component (eV) mom_den 1PE10.3 moment density of suprathermal electrons (cnts/cm**3) mom_temp 1PE10.3 moment temperature of suprathermal electrons (eV) DATA FLAG VALUES (-9.999E+10) 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 SITTLERETAL (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-BR-96.0SEC CONFIDENCE_LEVEL_NOTE = Confidence Level: ================== THIS DATA SET PROVIDES AN ESTIMATE OF THE ELECTRON PARAMETERS IN THE PLS ENERGY RANGE (10-5950 EV). THE THERMAL ELECTRON DENSITY MAY BE UNDERESTIMATED BY FACTORS OF 2 IN SOME REGIONS DUE TO NEGATIVE SPACECRAFT CHARGING. THERMAL ELECTRON PARAMETERS ARE ALSO UNRELIABLE INSIDE SIX KRONIAN RADII WHERE ELECTRON TEMPERATURES ARE COLD AND IN THE OCCULTATION REGIONS. HOT ELECTRONS ARE RELATIVELY UNDISTURBED BY CHARGING AND THESE PARAMETERS HAVE UNCERTAINTIES OF LESS THAN 20%. Data Coverage ================== Filename Records Start Stop -------------------------------------------------------------------- Volume ID: VG_1601 ELE_BR.TAB 1595 1980-11-12T00:00:30.505Z 1980-11-13T18:30:54.537Z Missing Data Flag ================== Any data column whose value is -9.999e+10 is a missing data value.