File: HE1MER_FMT.txt Version: NSSDC 11/15/2001 JFC --------------------------------------------------------------------- --------------------------------------------------------------------- The VMS binary data file HE1MER.BIN is not available at this site and can be retrieved from anonymous@nssdca.gsfc.nasa.gov at directory ANON_DIR:[COHO.HELIOS_1.MAG.MGD_FREEMAN]. --------------------------------------------------------------------- Hourly Average Merged Solar Wind Plasma and Field Data from Helios 1 Date Coverage: 1974-12-10 to 1980-12-29 Principal Investigators: Magnetometer - Fritz M. Neubauer Institute of Geophysics University of Koln Albertus-Magnus-Platz 50923 Koln, Germany Phone: 49-221-4702310 Email: neubauer@geo.uni-kochr.de Plasma Analyzer - Dr. Helmut R. Rosenbauer Max-Planck-Institut fur Aeronomie Postfach 20 37191 Katlenburg, Germany Internet: ROSENBAUER@LINMPI.DNET.GWDG.DE DECnet: ECD1::LINMPI::ROSENBAUER Data Contacts: Plasma Analyzer - Dr. Rainer Schwenn Max-Planck-Institut fur Aeronomie Postfach 20 37191 Katlenburg, Germany Internet: SCHWENN@LINAX1.MPAE.GWDG.DE DECnet: ECD1::LINMPI::SCHWENN Prof. John W. Freeman Department of Space Physics Rice University PO Box 1892 Houston, TX 77251 Internet: FREEMAN@ALFVEN.RICE.EDU DECnet: RICE::FREEMAN NSSDC Dataset ID's: Magnetic Field Data - 74-097A-01C (Helios 1) Plasma Data - 74-097A-09B (Helios 1) Dataset Description: This data set was compiled at NSSDC by Prof. J. W. Freeman of Rice University and consists of merged solar wind magnetic field and plasma data, plus heliocentric spacecraft coordinates, for interplanetary measurements by the fluxgate (Neubauer et al.) magnetometer and plasma analyzer (Rosenbauer et al.) experiments. File DATASET_NMC gives a brief data set description from information in the NSSDC Master Catalog. The Helios 1 merged data set consists of the ASCII text file, attached to the end of this file and describing the data set & format, and the VMS binary data file HE1MER.BIN. FORTRAN program READHEL.for converts selected parameters from the binary data files to ASCII file output format. Code HELTRJCON.for adds inertial heliographic longitude to READHEL output for spacecraft trajectory coordinates. ASCII versions of the magnetic field, plasma, and spacecraft position components of this data set are separately located in directories HELIOS_1/MAG/HOUR_NEUBAUER, HELIOS_1/PLASMA/HOUR, and HELIOS_1/TRAJ, respectively. The plasma and spacecraft position components of this data set have also been incorporated into the merged data set in HELIOS_1/MERGED, in which all vector and coordinate data have been transformed into the Heliographic/RTN system. Data Parameter Format: The merged data file is written in VMS binary. See the attached text file and the included *.fortran binary-to-ASCII conversion codes for details on the format. Related Information and Data: Further details on the spacecraft, experiment, data sets at NSSDC, and related WWW sites can be found on the Helios 1/2 flight project page under http://nssdc.gsfc.nasa.gov/space/ Hour averages of the interplanetary solar wind data from, and hourly heliocentric coordinates of, Helios 1/2 and other interplanetary spacecraft may be also be accessed and plotted on-line through the COHOWeb service based at the same WWW site as above. Acknowledgement: Use of these data in publications should be accompanied at minimum by acknowledgements of the National Space Science Data Center and the responsible Principal Investigator defined in the experiment documentation provided here. ****************************************************************************** HELIOS 1 AND 2 74-097A-01C, 74-097A-09B 76-003A-01C, 76-003A-09B THIS IS A DESCRIPTION OF THE MERGED SOLAR WIND AND IMF DATA FOR HELIOS 1 AND 2. THIS DATA SET CONSISTS OF ONE DATA TAPE. IT HAS BEEN CREATED BY SORTING AND MERGING THE 1 HOUR AVERAGE PLASMA DATA FROM THE HELIOS 1 AND 2 PLASMA EXPERIMENTS (74-097A-09A AND 76-003A -09A) AND 1 HOUR AVERAGE MAGNETOMETER DATA FROM HELIOS 1 AND 2 (74- 097A-01B AND 76-003A-01A). THE PLASMA DATA WERE PROVIDED BY RAINER SCHWENN AND THE MAGNETOMETER DATA BY F. M. NEUBAUER. THE CARRINGTON ROTATION NUMBER FOR AN EARTH OBSERVER AND THE CARRINGTON LONGITUDE OF THE SUBSPACECRAFT POINT HAVE BEEN CALCULATED AND ADDED TO THE DATA BY NSSDC. ALL DATA ARE ONE HOUR AVERAGES AND THE TIME TAG REFERS TO THE BEGINNING OF THE DATA AVERAGE INTERVAL IN SPACECRAFT EVENT TIME. THERE ARE THREE FILES ON THE TAPE: - FILE 1: THIS DOCUMENTATION - FILE 2: HELIOS 1 FROM 12/10/74 TO 12/29/80 - FILE 3: HELIOS 2 FROM 1/15/76 TO 3/4/80 DETAILS OF THE TAPE: << some of this information has been superceded >> ZZZZZZZZZZ - 9 TRACK - IBM 360 BINARY (32 BITS) - ALL WORDS ARE SINGLE PRECISION FLOATING POINT EXCEPT WORD 1, WHICH IS IN CHARACTERS (A4 FORMAT). THE DOCUMENTATION IS IN ASCII 8-BIT CHARACTERS, 80 PER RECORD. - EACH DATA FILE LOGICAL RECORD CONTAINS 30 WORDS (120 BYTES) - THE BLOCKSIZE IS 100 LOGICAL RECORDS. THE DATA WORDS REPRESENT THE FOLLOWING PARAMETERS: WORD NUMBER: 1. SPACECRAFT IDENTIFICATION: HE1=HELIOS 1 AND HE2=HELIOS 2 2. DATA CODE: 1 MEANS PLASMA DATA ONLY ARE PRESENT FOR THAT HOURLY INTERVAL; 2 MEANS MAGNETOMETER DATA ONLY; 3 MEANS BOTH PLASMA AND MAGNETOMETER DATA PRESENT. 3. YEAR OF THE DATA INTERVAL (LAST TWO DIGITS ONLY). 4. DAY OF THE DATA INTERVAL FROM THE FIRST DAY OF THE ABOVE YEAR, JAN. 1= DAY 1. 5. HOUR OF THE DAY OF THE DATA INTERVAL. 6. CUMMULATIVE DAY AND FRACTIONAL DAY SINCE JANUARY 1, 1972,EG. 1200 H SPACECRAFT TIME JAN. 1, 1972 = DAY 1.5. 7. SPACECRAFT HELIOCENTRIC DISTANCE IN ASTRONOMICAL UNITS. 8. CARRINGTON ROTATION NUMBER AS SEEN BY AN EARTH BASED OBSERVER AT THE START OF THE DATA INTERVAL. 9. CARRINGTON LONGITUDE OF THE SUBSPACECRAFT POINT ON THE SUN AT THE START OF THE DATA INTERVAL (IN DEGREES, 0-360). 10. HELIOGRAPHIC LATITUDE OF THE SUBSPACECRAFT POINT (IN DEGREES +,- 90). 11. EARTH-SUN-SPACECRAFT SEPARATION ANGLE (IN DEGREES, 0-360). 12. BXSE, THE COMPONENT OF THE INTERPLANETARY MAGNETIC FIELD ALONG THE X-SOLAR ECLIPTIC AXIS, POSITIVE TOWARD THE SUN (IN NANOTESLAS). 13. BYSE 14. BZSE 15. THE MAGNITUDE OF THE INTERPLANETARY MAGNETIC FIELD VECTOR (IN NANOTESLAS). 16. THE STANDARD DEVIATION OF BXSE (IN NANOTESLAS). 17. " " " BYSE " . 18. " " " BZSE " . 19. " " " OF THE MAGNITUDE OF THE MAGNETIC FIELD VECTOR (IN NANOTESLAS). 20. THE SOLAR WIND BULK FLOW SPEED (IN KM/S). 21. THE RADIAL COMPONENT OF THE PROTON TEMPERATURE (IN KILODEGREES KELVIN, IE. TO GET DEGREES, MULTIPLY BY 1000). 22. THE SOLAR WIND NUMBER DENSITY (IN PROTONS/CM3). 23. THE STANDARD DEVIATION OF BULK FLOW SPEED,WORD 20 (IN KM/S). 24. THE STANDARD DEVIATION OF THE PROTON TEMPERATURE, WORD 21 (IN KILODEGREES KELVIN). 25. THE STANDARD DEVIATION OF THE PROTON NUMBER DENSITY, WORD 22 (IN PROTONS/CM3). 26. THE PROTON FLOW ELEVATION ANGLE (IN DEGREES, + IS NORTH). 27. THE PROTON FLOW AZIMUTH ANGLE (IN DEGREES,+-180,+ IS EASTWARD FLOW; IE. THE ANGLE BETWEEN THE FLOW DIRECTION VECTOR AND THE LINE TO THE SUN IS POSITIVE IN THE COUNTER-CLOCKWISE DIRECTION LOOKING DOWN FROM THE NORTH ECLIPTIC POLE.) 28. THE ELEVATION ANGLE, THETA, OF THE MAGNETIC FIELD VECTOR IN THE SOLAR ECLIPTIC COORDINATE SYSTEM. 29. THE AZIMUTH ANGLE, PHI, OF THE MAGNETIC FIELD VECTOR IN THE SOLAR ECLIPTIC COORDINATE SYSTEM. 30. THE CUMMULATIVE WORD COUNT FOR THE FIRST WORD OF THE CURRENT LOGICAL RECORD FROM THE FIRST WORD OF THE FIRST DATA FILE. ADDITIONAL NOTES: THE CARRINGTON LONGITUDE GIVEN IN WORD 9 WAS CALCULATED USING THE EARTH-SUN-SPACECRAFT ANGLE AND THEREFORE DIFFERS SLIGHTLY FROM THAT IN THE ORGINAL PLASMA DATA SET. THE CARRINGTON ROTATION NUMBER , WORD 8, ALSO DIFFERS FROM THAT IN THE ORIGINAL PLASMA DATA SET. THE SPACECRAFT COORDINATES OTHER THAN THE CARRINGTON LONGITUDE ARE TAKEN FROM THE ORIGINAL PLASMA DATA SET EXCEPT WHEN NO PLASMA DATA EXISTS. AT THE START OF THESE TIMES, (MAGNETOMETER DATA ONLY) SMALL DISCONTINUITIES EXIST IN THE RADIAL DISTANCE, HELIOGRAPHIC LATITUDE AND EARTH-SUN-SPACECRAFT ANGLES DUE TO THE SLIGHT DIFFERENCES IN THESE VALUES IN THE TWO DATA SETS. REFERENCES: 1. H. ROSENBAUER, R. SCHWENN, E. MARSCH, B. MEYER, H. MIGGENRIEDER, M. D. MONTGOMERY, K. H. MUHLHAUSER, W. PILIPP, W. VOGES AND S. M. ZINK, A SURVEY ON INITIAL RESULTS OF THE HELIOS PLASMA EXPERIMENT, J. GEOPHYS.,42,561-580, 1977. 2. G. MUSMANN, F. M. NEUBAUER AND E. LAMMERS, RADIAL VARIATION OF THE INTERPLANETARY MAGNETIC FIELD BETWEEN 0.3 AND 1.0 AU: OBSERVATIONS BY THE HELOIS 1 SPACECRAFT, J. GEOPHYS.,42,591-598, 1977. END OF DOCUMENTATION