Data Set Overview : Version 1.1 ----------- This version 1.1 data set replaces the version 1.0 data set (DATA_SET_ID : VG2-J-MAG-4-48.0SEC) previously archived with the PDS. Changes to this version include the addition of data columns not included in version 1.0, the modification of time format and flag values, and upgrade of associated labels and catalog templates to PDS version 3.4. Data Set Description -------------------- This data set includes Voyager 2 Jupiter encounter magnetometer data from the Low Field Magnetometer (LFM) resampled at a 48 second sample rate. The data are given in Jovicentric System III right handed coordinates and have been averaged from the 60 ms instrument sample rate to a 48 second resampled rate. Ephemeris data, provided in 96 second sampled System III (1965) coordinates, have been merged into the data files for this data set. The ephemeris data, generated from Voyager 2 SEDR and provided by the Voyager MAG Team, are part of the data set VG2-J-POS-6-SUMM-S3COORDS-V1.1. The position vectors for times at which ephemeris is not provided have been flagged. The data set consists of the following columns: 1) UT of the sample in the format yyyy-mm-ddThh:mm:ss.sssZ, 2-4) spacecraft clock (m65536, mod60, fds-line), 5) magnetometer id (1 : LFM, 2 : HFM), 6) Br radial (Jupiter to spacecraft) B-field component, 7) Btheta (North/South system III B-field component, positive southward), 8) Bphi (azimuthal system III B-field component, positive eastward), 9) Bmag (magnitude of the averaged components), 10) avg_Bmag (average of the magnetic field magnitudes), 11) delta (latitude : arcsin(Btheta/Bmag)), 12) lambda (longitude : 180. - atan(Bphi/-Br)), 13-15) rms vectors, 16) sc_r (Jupiter to spacecraft range), 17) sc_lat (jovicentric latitude, positive northward), 18) sc_lon (jovicentric east longitude, system III 1965) 19) npts (number of points in average), 20) data flag - a flag value that indicates either software error or spacecraft hardware interference reduced confidence in this record (flag value of 1 is bad, 0 is good or unchecked). All magnetic field observations are measured in nanoTesla. The coordinate system for this data set is System (1965) III. All of the magnetic field data are calibrated (see the instrument calibration description for more details). The Jupiter System III coordinate system is defined in [DESSLER1983] and the reference documents for this data set are: [NESSETAL1979A], [LEPPINGETAL1981], [CONNERNEYETAL1981], [BEHANNONETAL1981]. For more information regarding the ephemeris data, please refer to the data set catalog file for the data set VG2-J-POS-6-SUMM-S3COORDS-V1.1. These data a provided in a conventional, right handed, spherical coordinate system with vectors R, Theta, and Phi. This system is sometimes referred to as System III (1965) right handed coordinates. The the magnetic field vectors are: BR - radial B-field component (along the Jupiter to spacecraft line) positive away from Jupiter BTHETA - North/South (system III) B-field component, positive southward BPHI - azimuthal (system III) B-field component, positive eastward System III (1965) spherical coordinates, the system in which the ephemeris data are expressed, is a jovicentric left handed system defined such that longitude increases with time as viewed by a stationary remote observer. R Jupiter to spacecraft range (positive away from Jupiter) LAT completes the left handed, orthogonal set LON System III (1965) east longitude (with longitude increasing eastward from a specific jovian prime meridian) Processing Level Id : 4 Software Flag : Y Processing Start Time : 1988-09-21 Parameters : Sampling Parameter Name : TIME Data Set Parameter Name : MAGNETIC FIELD VECTOR Sampling Parameter Resolution : 48.000000 Minimum Sampling Parameter : 19770820120000.000000 Maximum Sampling Parameter : UNK Sampling Parameter Interval : 48.000000 Minimum Available Sampling Int : 0.060000 Data Set Parameter Unit : NANOTESLA Noise Level : 0.006000 Sampling Parameter Unit : SECOND PARAMETER RESOLUTION DESCRIPTION NAME (UNITS) time 48 Sec time of the sample (UT) in the format yyyy-mm-ddThh:mm:ss.sssZ. The full sampling rate for the instrument is .06 +/- .006 sec. m65536, (counts) s/c clock mod 65536, mod 60 and mod60 and fds line fds_line mag_id n/a magnetometer ID magnetic (nT) measured parameter equaling the field magnetic field strength (e.g. in components nanoTeslas) along a particular axis (Br, Btheta, direction. Usually the three Bphi) orthogonal axis components are measured by three different sensors. magnetic (nT) derived parameter which combines the 3 field vector orthogonal magnetic field component (Bmag, avg_Bmag) measurements. delta n/a delta : arcsin(Btheta/Bmag) lambda n/a lambda : 180. - atan(Bphi/-Br) rms_Br, Pythagorean root mean square deviation rms_Bt, and of the component averages rms_Bp sc_r R[J] jovicentric (System III) spherical sc_lat degrees coordinates position vectors: range, sc_lon degrees latitude, and longitude npts (counts) the number of data points in the current average dflag n/a a character string which indicates software or s/c hardware intervention which reduces confidence in the data (NULL flags represent 'good' data) Source Instrument Parameters : Instrument Host ID : VG2 Data Set Parameter Name : MAGNETIC FIELD VECTOR Instrument Parameter Name : MAGNETIC FIELD COMPONENT Important Instrument Parameters : 1 Instrument Host ID : VG2 Data Set Parameter Name : MAGNETIC FIELD VECTOR Instrument Parameter Name : WAVE MAGNETIC FIELD INTENSITY Important Instrument Parameters : 1 Processing : Processing History ------------------ Source Data Set ID : N/A Software : UNK Product Data Set ID : VG2-J-MAG-4-48.0SEC Ancillary Data : An ancillary data file containing the derived spacecraft magnetic field is provided with this data at a 48 second sample rate. These data provide zero level offsets used in the data processing. S/C field data is provided in spacecraft coordinates as follows: PARAMETER RESOLUTION DESCRIPTION NAME (UNITS) time 48 sec time in format yyyy-mm-ddThh:mm:ss.sssZ m65536 n/a s/c clock mod 65536 mod60 n/a s/c clock mod60 mag_id n/a magnetometer ID Bx (nT) spacecraft coords. X component By (nT) spacecraft coords. Y component Bz (nT) spacecraft coords. Z component Bmag (nT) total magnetic field strength rms_Bx (nT) rms mag component rms_By (nT) rms mag component rms_Bz (nT) rms mag component npts (counts) number of points in average Data Coverage :Filename Records Start Stop-------------------------------------------------------------------Volume ID: VG_1502S3_48S.TAB 62578 1979-07-05T00:00:47.269Z 1979-08-12T16:55:08.608Z

Confidence Level Overview : This data set contains some data gaps and spikes. The data set does contain a flag value which has been provided by the PI (Norman Ness) that indicates whether or not a particular record has been contaminated by software error or by spacecraft interference (a flag value of 1 indicates a bad value, 0 indicates that the record has either not been evaluated or is good). Some records that are obviously contaminated have not been flagged. The hourly summary data will show a contamination code and data quality code of 2 when data in the hour have not been flagged but are obviously in error and a contamination code of 1 when the hour contains flagged records.