Data Set Information
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| DATA_SET_NAME |
VOYAGER 2 JUPITER PLASMA DERIVED ELECTRON MOMENTS 96 SEC
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| DATA_SET_ID |
VG2-J-PLS-5-ELE-MOM-96.0SEC
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| NSSDC_DATA_SET_ID |
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| DATA_SET_TERSE_DESCRIPTION |
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| DATA_SET_DESCRIPTION |
Data Set Overview : THIS DATA SET CONTAINS THE DERIVED VALUES FOR THE ELECTRON MOMENT DENSITY AND TEMPERATURE AT JUPITER IN THE PLS ENERGY RANGE (10-5950 EV) DURING THE VOYAGER 2 ENCOUNTER. ADJACENT LOW AND HIGH ENERGY ELECTRON MEASUREMENTS ARE COMBINED TO FORM A COMPOSITE SPECTRA WHICH IS USED FOR THE MOMENT CALCULATION. THE MOMENT CALCULATIONS ARE PERFORMED AS DESCRIBED IN SCUDDER ET AL. (1981). THESE ASSUME ISOTROPIC DISTRIBUTIONS AND CORRECT FOR POSITIVE SPACECRAFT CHARGE WHEN APPLICABLE AND INTERPOLATE ELECTRON SPECTRA BELOW THE 10 EV INSTRUMENT THRESHOLD BEFORE PERFORMING THE INTEGRATION OVER VELOCITY. DATA FORMAT: COLUMNS 1-6 ARE TIME (YEAR, DAY, HOUR, MIN, SEC, MSEC) COLUMN 7 IS THE MOMENT DENSITY IN CM-3, COLUMN 8 THE TEMPERATURE IN EV. EACH ROW HAS FORMAT (6I4, 2E12.3). 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 SCUDDER ET AL. (1981) AND A COMPLETE INSTRUMENT DESCRIPTION CAN BE FOUND IN BRIDGE (1977). Processing Level Id : 5 Software Flag : Y Processing Start Time : UNK Processing Stop Time : UNK 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 : VG2 Data Set Parameter Name : ELECTRON DENSITY Instrument Parameter Name : ELECTRON RATE Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ELECTRON DENSITY Instrument Parameter Name : ELECTRON CURRENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ELECTRON TEMPERATURE Instrument Parameter Name : ELECTRON RATE Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : ELECTRON TEMPERATURE Instrument Parameter Name : ELECTRON CURRENT Important Instrument Parameters : 1 Processing : Processing History ------------------ Source Data Set ID : VG2-PLS Software : UNK Product Data Set ID : VG2-J-PLS-5-ELE-MOM-96.0SEC
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| DATA_SET_RELEASE_DATE |
1988-08-01T00:00:00.000Z
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| START_TIME |
1979-07-06T12:00:42.687Z
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| STOP_TIME |
1979-07-09T11:59:06.436Z
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| MISSION_NAME |
COMET SL9/JUPITER COLLISION
VOYAGER
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| MISSION_START_DATE |
1993-01-01T12:00:00.000Z
1972-07-01T12:00:00.000Z
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| MISSION_STOP_DATE |
1996-01-01T12:00:00.000Z
N/A (ongoing)
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| TARGET_NAME |
JUPITER
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| TARGET_TYPE |
PLANET
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| INSTRUMENT_HOST_ID |
VG2
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| INSTRUMENT_NAME |
PLASMA SCIENCE EXPERIMENT
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| INSTRUMENT_ID |
PLS
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| INSTRUMENT_TYPE |
PLASMA ANALYZER
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| NODE_NAME |
Planetary Plasma Interactions
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| ARCHIVE_STATUS |
ARCHIVED
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| CONFIDENCE_LEVEL_NOTE |
Overview : THIS DATA SET PROVIDES THE BEST ESTIMATE AVAILABLE OF THE TOTAL ELECTRON DENSITY IN THE PLS ENERGY RANGE (10-5950 EV). FOUR ASSUMPTIONS WERE MADE 1) SECONDARY ELECTRONS ESCAPING FROM THE COLLECTOR PLATE OF THE DETECTOR WERE NEGLECTED; 2) EXTRAPOLATIONS WERE MADE TO ESTIMATE THE NUMBER OF ELECTRONS OUTSIDE THE PLS ENERGY RANGE; 3) ELECTRONS WERE ASSUMED TO HAVE ISOTROPIC DISTRIBUTIONS; 4) WHERE THE SPACECRAFT POTENTIAL WAS SMALL THE SHAPE OF THE THERMAL ELECTRON SPECTRA WAS USED TO ESTIMATE THE CHARGE AND CORRECT THE DERIVED DENSITIES. 1) SHOULD RESULT IN AN UNDERESTIMATE OF THE ELECTRON DENSITY BY NO MORE THAN 10% FOR TE < 100EV AND NO MORE THAN 30% FOR TE > 100EV. 2) GIVES UNCERTAINTIES OF AT MOST 10%, AND USUALLY MUCH SMALLER, FOR TE : 5-3000 EV WHICH IS THE TE RANGE MEASURED IN THIS REGION. 3) SHOULD BE AN EXCELLENT ASSUMPTION SINCE ISOTROPIZATION TIMES FOR ELECTRONS ARE FAST, AND SINCE THE ELECTRON THERMAL SPEED IS ALWAYS MUCH GREATER THAN THE PLASMA FLOW SPEED. 4) IN REGIONS WHERE THE SPACECRAFT CHARGE IS POSITIVE, CHARGING PRODUCES UNCERTAINTIES OF AT MOST 10%. VALUES OF TE IN ALL REGIONS HAVE UNCERTAINTIES APPROXIMATELY EQUAL TO THE DENSITY UNCERTAINTIES.
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| CITATION_DESCRIPTION |
Citation TBD
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| ABSTRACT_TEXT |
THIS DATA SET CONTAINS THE DERIVED VALUES FOR THE ELECTRON MOMENT DENSITY AND TEMPERATURE AT JUPITER IN THE PLS ENERGY RANGE (10-5950 EV) DURING THE VOYAGER 2 ENCOUNTER. ADJACENT LOW AND HIGH ENERGY ELECTRON MEASUREMENTS ARE COMBINED TO FORM A COMPOSITE SPECTRA WHICH IS USED FOR THE MOMENT CALCULATION. THE MOMENT CALCULATIONS ARE PERFORMED AS DESCRIBED IN SCUDDER ET AL. (1981). THESE ASSUME ISOTROPIC DISTRIBUTIONS AND CORRECT FOR POSITIVE SPACECRAFT CHARGE WHEN APPLICABLE AND INTERPOLATE ELECTRON SPECTRA BELOW THE 10 EV INSTRUMENT THRESHOLD BEFORE PERFORMING THE INTEGRATION OVER VELOCITY. DATA FORMAT: COLUMNS 1-6 ARE TIME (YEAR, DAY, HOUR, MIN, SEC, MSEC) COLUMN 7 IS THE MOMENT DENSITY IN CM-3, COLUMN 8 THE TEMPERATURE IN EV. EACH ROW HAS FORMAT (6I4, 2E12.3). 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 SCUDDER ET AL. (1981) AND A COMPLETE INSTRUMENT DESCRIPTION CAN BE FOUND IN BRIDGE (1977).
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| PRODUCER_FULL_NAME |
JOHN D. RICHARDSON
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| SEARCH/ACCESS DATA |
Planetary Plasma Interactions Website
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