File: HE1PLAHR_FMT.txt                       Version: NSSDC 11/15/2001 JFC
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HELIOS 1 INTERPLANETARY SOLAR WIND PLASMA DATA

Time Coverage: 12/12/74 - 12/29/80

Data Parameter Description:

 NY      - YEAR OF THE DATA INTERVAL (LAST TWO DIGITS ONLY). 
 ND      - DAY OF THE DATA INTERVAL FROM THE FIRST DAY OF THE ABOVE YEAR,  
           JAN. 1= DAY 1.  
 NH      - HOUR OF THE DAY OF THE DATA INTERVAL.                      
 SWSPD   - THE SOLAR WIND BULK FLOW SPEED (IN KM/S).  
 TPRADK  - THE RADIAL COMPONENT OF THE PROTON TEMPERATURE (IN DEGREES 
           KELVIN).
 SWPDEN  - SOLAR WIND NUMBER DENSITY (IN PROTONS/CM3).                
 PFELEV  - PROTON FLOW ELEVATION ANGLE (IN DEGREES, + IS NORTHWARD FLOW WITH
           RESPECT TO THE ECLIPTIC PLANE).
 PFAZIM  - PROTON FLOW AZIMUTH ANGLE (IN DEGREES, +-180; ZERO DEGREES IS IN
           THE DIRECTION OPPOSITE TO THE X-AXIS IN THE SPACECRAFT-CENTERED
           SOLAR ECLIPTIC [SSE] SYSTEM; AZIMUTH INCREASES POSITIVELY IN THE
           DIRECTION OF PLANETARY MOTION AROUND THE SUN, OPPOSITE TO THE
           Y-AXIS OF THE SSE SYSTEM).  

 The Spacecraft-Centered Solar Ecliptic (SSE) system is analogous to the
 Geocentric Solar Ecliptic (GSE) system, in that the X-axis points from
 the central body (the spacecraft) towards the Sun, the Z-axis is directed
 towards Ecliptic North, and the Y-axis lies in the Ecliptic and is directed
 opposite to the direction of planetary motion around the Sun. The plasma
 flow angles are measured with respect to the negative X-axis in the SSE
 system, so that zero degrees corresponds to outward radial flow in for
 both angles.

File Parameter Format:

      WRITE(20,130) NY,ND,NH,SWSPD,TPRADK,SWPDEN,PFELEV,PFAZIM
130   FORMAT(1X,I2,1X,I3,1X,I2,F8.2,2E10.3,2F7.2)

Data Source: Plasma parameters extracted from merged data set (NSSDC ID
74-097A-01C or 74-097A-09B) in directory MGD_FREEMAN with code READHEL.for. 

Note: proton flow angles in this directory before 3/26/93 were in error and
should be recopied from the current files.

Reference: 

     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. 


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.