File: p11mgd.txt ----------------------------------------------------------------------------- PIONEER-11 INTERPLANETARY SOLAR WIND PLASMA AND MAGNETIC FIELD DATA Data Set Date Coverage: 1973-04-06 to 1992-08-01 NSSDC Data Set ID: SM-41F (NSSDC Heliospheric CD-ROM) Experiments: Pioneer 11 Helium Vector Magnetometer (HVM) Pioneer 11 Plasma Science (PLS) Experiment Principal Investigators: HVM - Dr. Edward J. Smith, NASA Jet Propulsion Laboratory, Pasadena, CA PLS - Dr. Aaron Barnes, NASA Ames Research Center, Moffett Field, CA Data Set Description: The main science objectives for the PIONEER interplanetary mission are as follows: - search for the heliospheric boundary with interstellar space; - study the large-scale structure of the solar wind plasma and interplanetary magnetic field within the heliosphere; - investigate propagation of solar and galactic energetic particles in the heliosphere; - measure the radial gradient, spectra, and nuclear composition of the anomalous cosmic rays from the solar wind termination shock; - study acceleration of energetic particles by solar flare shocks and corotating interaction regions within the heliosphere. PI of magnetic field data: Dr. Edward J. Smith, NASA JPL. PI of plasma data: Dr. Aaron Barness, Ames Research Center, NASA. For the hourly resolution records, this directory contains hourly averages of parameters for the interplanetary magnetic field (1973-Apr-6 - 1992-Aug-1), solar wind plasma (1973-Apr-21 - 1992-May-30), and spacecraft trajectory coordinates (1973-Apr-6 - 1992-Aug-1). Time Coverage of merged files: April 6, 1973 - August 1, 1992 Data Set Format: Pioneer-11 data have been reprocessed to ensure a uniformity of content and coordinate systems relative to data from other deep- space missions: - All spacecraft trajectory data were transformed to a Heliographic Inertial (HGI) coordinate system. - merging of trajectory coordinates, magnetic field data, and plasma data files into a single annual file P11_YR.DAT, where YR is the year; - Data gaps were filled with dummy numbers for the missing hours or entire days to make all files of equal length. The character '9' is used to fill all fields for missing data according to their format, e.g. ' 9999.9' for a field with the FORTRAN format F7.1. Note that format F7.1 below really means (1X,F6.1),etc. For the daily resolution data (one file), simple averages were taken over the hourly values. The format is identical to that for the hour averages However, the "hour" field has 0 as a value.and the "Magnitude of Average Vector" field is the simple average of the 24 hourly values of this parameter. Format Description: WORD ASCII MEANING UNITS/COMMENTS 1 I4 YEAR 1980......... 2 I4 DECIMAL DAY January 1 =Day 1 3 I3 HOUR (0,1,......23) 4 F7.2 Spacecraft Heliocentric astronomical units Distance 5 F7.1 Heliographic Inertial Latitude degrees, +/- 90 of the spacecraft position 6 F7.1 Heliographic Inertial Longitude degrees, 0-360 of the spacecraft position 7 F9.4 BR RTN coordinate system NANOTESLAS 8 F9.4 BT RTN coordinate system NANOTESLAS 9 F9.4 BN RTN coordinate system NANOTESLAS 10 F9.4 Scalar B NANOTESLAS 11 F7.1 Bulk flow speed, RTN km/s 12 F7.1 THETA-elevation angle Degrees of flow velocity vector (RTN-cordinate system) 13 F7.1 PHI- azimuth angle of Degrees flow velocity vector. (RTN-coordinate system) 14 F9.4 Proton density [n/cc] 15 F9.0 Proton Temperature degrees, K DESCRIPTION OF COORDINATE SYSTEMS The Heliographic Inertial (HGI) coordinates are Sun-centered and inertially fixed with respect to an X-axis directed along the intersection line of the ecliptic and solar equatorial planes. The solar equator plane is inclined at 7.25 degrees from the ecliptic. This direction was towards ecliptic longitude of 74.36 degrees on 1 January 1900 at 1200 UT; because of precession of the celestial equator, this longitude increases by 1.4 degrees/century. The Z axis is directed perpendicular and northward from the solar equator, and the Y-axis completes the right-handed set. This system differs from the usual heliographic coordinates (e.g. Carrington longitudes) which are fixed in the frame of the rotating Sun. The RTN system is fixed at a spacecraft (or the planet). The R axis is directed radially away from the Sun, the T axis is the cross product of the solar rotation axis and the R axis, and the N axis is the cross product of R and T. At zero Heliographic Latitude when the spacecraft is in the solar equatorial plane the N and solar rotation axes are parallel. Related Information and Data: Hour averages of the interplanetary solar wind data from, and hourly heliocentric coordinates of, Pioneer 10/11 and other interplanetary spacecraft may be also be accessed and plotted on-line through the COHOWeb service: http://cohoweb.gsfc.nasa.gov/ 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. Citation of NSSDC's Coordinated Heliospheric Observations (COHO) data base would also be appreciated, so that other potential users will be made aware of this service. ---------------------------------------------------