Data Set Information
|
| DATA_SET_NAME |
VG1 LECP 0.4S HIGH RESOLUTION JUPITER FAR ENCOUNTER DATA
|
| DATA_SET_ID |
VG1-J-LECP-3-RDR-FAR-ENC-400MSEC-V1.0
|
| NSSDC_DATA_SET_ID |
|
| DATA_SET_TERSE_DESCRIPTION |
Voyager 1 Energetic Particle (LECP) data from the Jupiter far
encounter periods from 1979-02-28T09:00:11 to 1979-03-04T21:38:58,
and from 1979-03-06T08:18:21 to 1979-03-11T13:00:18.
The data set provides 0.4 second counting rates.
|
| DATA_SET_DESCRIPTION |
Data Set Overview
=================
Data Set Description
--------------------
This far encounter data set consists of electron and ion
counting rate data from the Low Energy Charged Particle (LECP)
experiment on Voyager 1 while the spacecraft was within the
vicinity of Jupiter. This instrument measures the intensities
of in-situ charged particles ( >15 keV electrons and >30 keV
ions) with various levels of discrimination based on energy
range and mass species. A subset of almost 100 LECP channels
are included in this data set. The LECP data are globally
calibrated to the extent possible. During Jupiter far
encounter, the entire LEPT (Low Energy Particle Telescope)
and part of the LEMPA (Low Energy Magnetospheric Particle
Analyzer) subsystems were turned on for data collection.
Particles include electrons, protons, alpha particles, and
light, medium, and heavy nuclei particles. The far encounter
data are 0.4 second rate measurements within 1/8 of the LECP
instrumental motor rotation period (the angular scanning
periods, or step period).
The LECP instrument has a rotating head for obtaining angular
anisotropy measurements of the medium energy charged particles.
A gear-drive motor steps through eight equal angular sectors
per revolution for data collection. The cycle time for the
rotation is 48 minutes or 25.6 minutes during cruise mode,
and 192 second or 48 second during the planetary encounter.
The data were originally collected in the form of 'rates',
which were not always converted into the usual physical
units. The reason is that such a conversion would depend on
uncertain determinations such as the mass species of the
particles and the level of background. Both mass species
and background are generally determined from context during
the study of particular regions. To convert 'rate' to
'intensity' for a particular channel one performs the
following tasks: 1) decide on the level of background
contamination and subtract that off the given rate level.
Background is to be determined from context and from making
use of sector 8 rates (sector 8 is covered by a 2 mm
Aluminium sunshield and used for data calibration).
2) Divide the background corrected rate by the channel
geometric factor and by the energy bandpass of the channel.
To determine the energy bandpass, one must judge the mass
species of the detected particles (for ions but not for
electrons). The energy band passes are given in the form
of 'energy/nucleon'. For channels that begin their names
with the designations 'ch' these bandpasses can be used on
mass species that are accepted into that channel, which
gives the minimum and maximum 'Z' value accepted -- these
entries are blank for electron channels). For other channels
the given bandpass refers only to the lowest 'Z' value
accepted. The bandpasses for other 'Z' values are not all
known, but some are given in the literature (e.g.
[KRIMIGISETAL1979A]). The final product of these
instructions will be the particle intensity in the
unit of 'counts/(cm**2 sr sec keV)'. LECP data can
also be in the form of flux, whose unit is
'cm**-1 sr**-1 sec**-1'.
Far Encounter Channel Definitions for Voyager 1 LECP
CH CH LOW HIGH MEAN GEOMETRIC CH
Num NAME (MeV/N) (MeV/N) (Mev/N) FACTOR LOGIC
cm**2 sr DEFINITIN
--------------------------------------------------------
1 EB01 0.015 0.037 0.020 0.00600
2 EBD1 0.015 0.500 0.020 0.00012
3 EB02 0.037 0.061 0.045 0.00600
4 EBD2 0.037 0.500 0.045 0.00012
5 EB03 0.070 0.112 0.090 0.00600
6 EBD3 0.070 0.500 0.090 0.00012
7 EB04 0.130 0.183 0.120 0.00600
8 EBD4 0.130 0.500 0.120 0.00012
9 EB05 0.200 0.500 0.200 0.00600
10 EBD5 0.200 0.500 0.200 0.00012
11 EG06 0.252 2.000 0.250 0.00200
12 EG07 0.480 2.000 0.500 0.00200
13 EG08 0.853 2.000 0.900 0.00200
14 EG09 2.100 5.000 2.000 0.00200
15 E44 0.350 1.500 0.500 1.31000
16 E45 2.500 100.000 2.000 1.31000
17 E37 6.000 100.000 6.000 1.31000
18 PL01 0.030 0.053 0.025 0.04020
19 PL02 0.053 0.085 0.050 0.04020
20 PL03 0.085 0.139 0.100 0.04020
21 PL04 0.139 0.200 0.150 0.04020
22 PL05 0.200 0.550 0.250 0.04020
23 PL06 0.540 1.050 0.600 0.04020
24 PL07 1.050 2.030 1.000 0.04020
25 PL08 2.030 4.010 2.500 0.04020
26 P32 0.310 0.610 0.350 0.09750 E0E2(E3)
27 P1 0.570 0.890 0.600 0.44100 E1E2(E3)
28 P10 4.400 9.200 5.000 0.53900 E2E3(E4)
29 P11 9.200 21.000 12.000 0.53900 E2E3(E4)
30 P16 3.400 18.000 5.000 1.50000 E5E4(E3)
31 P23 22.000 31.000 25.000 1.31000 E5E4E3(E2)
32 P27 34.000 72.000 50.000 1.20000 E5E4E3E2
33 P31 211.000 1000.000 250.000 1.31000 E4E3
34 A39 0.100 0.203 0.100 0.09750 E0(E2)
35 A33 0.200 0.510 0.350 0.09750 E0E2(E3)
36 A46 0.147 2.000 0.600 0.44100 'D1F1,CA'
37 A3 0.460 1.800 0.600 0.44100 E1E2(E3)
38 A4 1.900 4.000 2.500 0.44100 E1E2(E3L12)
39 A12 4.200 7.800 5.000 0.53900 E2E3(E4L23)
40 A13 7.800 21.000 15.000 0.53900 E2E3(E4L23)
41 A17 3.300 69.000 5.000 1.50000 E5E4(E3L54
42 A24 22.000 31.000 25.000 1.31000 E5E4E3(E2)
43 A28 33.000 62.000 50.000 1.20000 E5E4E3E2
44 AL01 0.980 1.770 1.000 0.04020
45 AL02 1.770 4.220 2.500 0.04020
46 M34 0.150 0.180 0.200 0.09750 E0E2
47 L5 0.470 5.600 1.500 0.44100 E1E2(E3L12)
48 L14 5.800 28.000 6.000 0.53900 E2E3(E4L23)
49 L18 6.800 28.000 5.000 1.50000 E5E4(E3L54
50 M38 0.072 0.150 0.100 0.09750 E0(E2)
51 M35 0.180 0.280 0.250 0.09750 E0E2(E3)
52 M47 0.124 14.300 0.250 0.44100 D1F2
53 M6 0.530 5.600 0.500 0.44100 E1E2(E3L12)
54 M7 6.170 8.600 6.000 0.44100 E1E2(E3L12)
55 M15 9.500 46.000 15.000 0.53900 E2E3(E4L23)
56 M19 6.800 10.400 6.000 1.50000 E5E4(E3L54)
57 M20 10.400 40.000 15.000 1.50000 E5E4(E3L54)
58 M25 48.000 64.000 50.000 1.31000 E5E4E3(E2)
59 M29 68.000 270.000 70.000 1.20000 E5E4E3E2
60 H36 0.099 0.140 0.100 0.09750 E0(E2)
61 H8 0.310 2.200 0.350 0.44100 E1E2(E3)
62 H9 2.300 12.000 2.000 0.44100 E1E2(E3)
63 H43 13.000 82.000 15.000 0.53900 E2E3(E4)
64 H21 9.500 18.000 10.000 1.50000 E5E4(E3L54)
65 H22 19.000 78.000 25.000 1.50000 E5E4(E3L54)
66 H26 82.000 120.000 100.000 1.31000 E5E4E3
67 H30 127.000 850.000 150.000 1.20000 E5E4E3E2
68 AR SINGLES
69 E0 SINGLES
70 E1 SINGLES
71 E2 SINGLES
72 E3 SINGLES
73 E4 SINGLES
74 E5 SINGLES
75 AL SINGLES
76 ALAR SINGLES
--------------------------------------------------------
Far encounter data are stored in files for channels from
different rate groups indicated by the file names, e.g.
V1YYDOY{A,B,...,H}MG{01,02, ..., 16}.CSV
------- --------- --------------
| | | | |
| | | | rate group number
| | | |
| | | starting time A: 00:00:00
| | | B: 03:00:00
| | | C: 06:00:00
| | | D: 09:00:00
| | | E: 12:00:00
| | | F: 15:00:00
| | | G: 18:00:00
| | | H: 21:00:00
| | |
| | 3-digit day of year
| |
| 2-digit year
|
Voyager 1
Rate group definitions are listed as below:
-------------------------------------------------------
rate channel names
group in
# the rate group
-------------------------------------------------------
1 PL01 PL02 PL03 EB04 EBP04
2 EB01 EBP01 EB02 EBP02 EB03 EBP03 EG06
3 A39 A33 P32 P31
4 EG07 EG08 EG09 EB05 EBP05
5 P1 E44 A3 P10
6 PL04 PL08 AR E0 E1 E2 E3 E4 E5 AL P16
7 P11 P23 P27 A4
8 A46 A13 M47 A17 A28 M38
9 M35 PL05 PL06 PL07
10 E45 ALAR? A12 A24
11 M34 L5 L18 L14
12 M6 M7 M19 H36
13 H8 H43 M25 H9
14 M29 H22 H26 H30
15 AL01 AL02 E37 H21
16 M15 M20
-------------------------------------------------------
Far encounter data file has the format described as:
==================================================================
name data type description
------------------------------------------------------------------
TIME char time in the format 'yyyy-mm-dd hh:mm:ss.sss '
STEP int step position (0-7)
MOTOR_MOVEMENT int motor movement: 0 - no movement, 1 - movement
during accumulation
CH1_RATE real counts measured during accumulation interval
ACC_TIME_CH1 real accumulation time for CH1
CH2_RATE real counts measured during accumulation interval
ACC_TIME_CH2 real accumulation time for CH2
...
...
...
CHn_RATE real counts measured during accumulation interval
ACC_TIME_CHn real accumulation time for CHn
where n is determined by the above table given rate group number.
Parameters
==========
Processing Level Id : 3
Software Flag : Y
Processing Start Time : UNK
Electron Rate
-------------
Sampling Parameter Name : TIME
Data Set Parameter Name : ELECTRON RATE
Sampling Parameter Resolution : 0.400000
Sampling Parameter Interval : 0.400000
Data Set Parameter Unit : COUNTS
Noise Level : 0.000000
Sampling Parameter Unit : SECOND
A measured parameter equaling the number of electrons hitting
a particle detector per specified accumulation interval. The
counted electrons may or may not be discriminated as to their
energies (e.g. greater than E1, or between E1 and E2).
Ion Rate
--------
Sampling Parameter Name : TIME
Data Set Parameter Name : ION RATE
Sampling Parameter Resolution : 0.400000
Sampling Parameter Interval : 0.400000
Data Set Parameter Unit : COUNTS
Noise Level : 0.000000
Sampling Parameter Unit : SECOND
A measured parameter equaling the number of ions striking a
particle detector per specified accumulation interval. The
counted ions may or may not be discriminated as to their
energies (e.g. energy/nucleon or energy/charge between E1 and
E2 or greater than E1) and/or as to their ion composition
(atomic number Z or mass number greater than Z1 or M1, or
between Z1 and z2 or M1 and M2).
Source Instrument Parameters
============================
Instrument Host ID : VG1
Data Set Parameter Name : ELECTRON RATE
Instrument Parameter Name : ELECTRON RATE
Important Instrument Parameters : 1
Instrument Host ID : VG1
Data Set Parameter Name : ION RATE
Instrument Parameter Name : ION RATE
Important Instrument Parameters : 1
|
| DATA_SET_RELEASE_DATE |
2002-08-21T00:00:00.000Z
|
| START_TIME |
1979-02-28T09:00:11.940Z
|
| STOP_TIME |
1979-03-11T01:00:17.450Z
|
| MISSION_NAME |
VOYAGER
|
| MISSION_START_DATE |
1972-07-01T12:00:00.000Z
|
| MISSION_STOP_DATE |
N/A (ongoing)
|
| TARGET_NAME |
JUPITER
|
| TARGET_TYPE |
PLANET
|
| INSTRUMENT_HOST_ID |
VG1
|
| INSTRUMENT_NAME |
LOW ENERGY CHARGED PARTICLE
|
| INSTRUMENT_ID |
LECP
|
| INSTRUMENT_TYPE |
CHARGED PARTICLE ANALYZER
|
| NODE_NAME |
Planetary Plasma Interactions
|
| ARCHIVE_STATUS |
ARCHIVED
|
| CONFIDENCE_LEVEL_NOTE |
Confidence Level Overview
=========================
At all times during this planetary encounter there exist data
in this data set that can be rated with the highest confidence
level. However, some of the channels of data are contaminated
by various kinds and various levels of contaminations. It is
therefore imperative, in using this data set, that the
contamination tables within the catalog be examined. Also, not
all kinds of contamination have been fully documented. When in
doubt the data supplier must be contacted.
Some channels are subject to serious contaminations, and many
of these contaminations cannot be removed except with a region-
by-region analysis, which has not been done for this data.
Thus, to use this data it is absolutely vital that the
contamination types ('CONTAMINATION_ID' , 'CONTAMINATION_DESC')
and the levels of contamination ('DATA_QUALITY_ID'
corresponding to the definitions 'DATA_QUALITY_DESC') be
carefully examined for all regions of study. A dead time
correction procedure has been applied in an attempt to correct
the linear effects of detector overdrive (pulse-pileup). This
procedure does not fix severely overdriven detectors. A
procedure is available for correcting Voyager 2 LECP electron
contamination of low energy ion channels, but its effectiveness
has been evaluated only for the Uranus data set. Thus,
corrections have been applied only to the Uranus data set.
Missing Data Flag
=================
Any data column whose value is NULL is a missing data value.
|
| CITATION_DESCRIPTION |
Krimigis, S. M., Mauk, B. H., Armstrong, T. P.,
VG1-J-LECP-3-RDR-FAR-ENC-400MSEC-V1.0,
VG1 LECP 0.4S HIGH RESOLUTION JUPITER FAR ENCOUNTER DATA,
NASA Planetary Data System, 2002.
|
| ABSTRACT_TEXT |
This far encounter data set consists of electron and ion
counting rate data from the Low Energy Charged Particle (LECP)
experiment on Voyager 1 while the spacecraft was within the
vicinity of Jupiter. This instrument measures the intensities
of in-situ charged particles ( >15 keV electrons and >30 keV
ions) with various levels of discrimination based on energy
range and mass species. A subset of almost 100 LECP channels
are included in this data set. The LECP data are globally
calibrated to the extent possible. Particles include electrons,
protons, alpha particles, and light, medium, and heavy nuclei
particles.
|
| PRODUCER_FULL_NAME |
BARRY H. MAUK
|
| SEARCH/ACCESS DATA |
Planetary Plasma Interactions Website
|
|
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