Voyager 1 48-s Triaxial Fluxgate Magnetometer (MAG) Magnetic Field Data Near and Beyond Termination Shock in ASCII Format

The main science objectives for the VOYAGER interplanetary mission are as
follows:
- investigate the structure of the solar wind magnetic fields and plasma in the
inner and outer heliosphere;
- conduct long term study of heliospheric evolution during different phases of
the twenty-two year solar magnetic cycle and the eleven-year solar activity
cycle;
- study the long term solar modulation and determine the elemental and isotopic
abundances of galactic cosmic ray particles in the heliosphere;
- measure radial gradients, spectra, and nuclear abundances of the anomalous
component of cosmic rays from acceleration at the solar wind termination
shock;
- investigate local particle acceleration in the interplanetary medium from
solar flare shocks and corotating interaction regions;
- study propagation of solar energetic particles in the heliosphere.
The average magnetic field strength produced by the spacecraft at the location
of the outboard magnetometer of the dual magnetometers system on V1 and V2 is
about 0.1 - 0.2 nT, comparable to the most probable magnetic field strength in
the inner heliosheath and significantly larger than the most probable magnetic
field strength in the distant supersonic solar wind. The spacecraft magnetic
field is a complex, time-dependent signal that must be removed from the measured
magnetic field signal in order to derive the ambient magnetic fields of the
solar wind and heliosheath. Corrections must also be made for spurious magnetic
signals and noise associated with the telemetry system, ground tracking systems,
and other factors. Extracting the signal describing the solar wind and
heliosheath from the many sources of uncertainty is a complex and partly
subjective process that requires understanding of the instrument and judgment
based on experience in dealing with the ever-changing extraneous signals. We
estimate that for the V1 MAG data the 1-sigma the uncertainty the 48 sec
averages for each of the components of the magnetic field BR, BT, and BN is
typically +/- 0.02 nT; the uncertainty in magnitude F1 is typically +/- 0.03 nT.
F1, BR, BT, and BN can differ from one another and they may vary with time, but
there is no practical way to determine these uncertainties more precisely at
present.

References

Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer,
Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Science Reviews, 21 (3), 235-257, 1977.

Burlaga, L.F., Merged interaction regions and large-scale magnetic field fluctuations during 1991 -
Voyager-2 observations, J. Geophys. Res., 99 (A10), 19341-19350, 1994.

Burlaga, L.F., N.F. Ness, Y.-M. Wang, and N.R. Sheeley Jr., Heliospheric magnetic field strength and
polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002.

Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., , 76, 3564, 1971.