File: HE1MGA_FMT.txt                   Version: NSSDC 11/15/2001 JFC 
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Helios 1 Interplanetary Magnetic Field, Hourly Averages, 1974 - 1981

Date Coverage:  1974-12-14 to 1981-06-14

Sensor: Helios 1 Triaxial Fluxgate Magnetometer for Average Fields

Principal Investigator: Prof. Norman F. Ness
                        Bartol Research Institute
                        Univ. of Delaware
                        217 Sharp Laboratory
                        Newark, DE   19716
                        DECnet: BARTOL::NFNESS

Data Contact: Prof. Franco Mariani
              Istituto di Fisica G. Marconi
              Piazzale A. Moro 2
              00185 Roma, Italy
              Internet: MARIANI@ROMA2.INFN.IT
              DECnet: 40007::MARIANI

NSSDC Dataset ID: 74-097A-02C

Description: This data set contains hour-averaged magnetic field vectors from
the the Ness/Mariani experiment on Helios 1 [or 2]. Each record contains time,
magnetic field intensity and cartesian components in spacecraft-centered solar
ecliptic coordinates, standard deviations, numbers of fine-scale points in the
average, and an instrument mode indicator. It should be noted that the
"average" mode, which was used a minority of the time and involved on-board
averaging, may have incorrectly handled range changes caused by occasional
significant changes in ambient field intensity. The data set had not been
filtered for this effect upon delivery to NSSDC. The data files are named
either HE1MGA.asc, for one file covering the entire 1974 - 1981 period,
or HE1MGAyy.asc, for one year intervals of data. 

Data Format: ASCII, 12 parameters/record

   FORTRAN record format > format(1x,I1,3I4,4F7.2,2F6.2,I6,I2)

	word #		content
	1		s/c # (1=HELIOS1, 2=HELIOS2)
	2		last 2 digits of the year
	3		day of the year
	4		hour
	5		Bx
	6		By
	7		Bz
	8		<|B|>
	9		StD in field vector (*)
	10		StD of <|B|> (word 8)
	11		# of 6 sec averages in each hourly average
	12		mode: 0=detailed, 1=average


   (*) sqrt(StD(Bx)**2+StD(By)**2+StD(Bz)**2)
       where StD=standard deviation


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.