Open AccessHeliospheric magnetic field strength out to 66 AU: Voyager 1, 1978–1996
Author(s) -
Burlaga L. F.,
Ness N. F.,
Wang Y.M.,
Sheeley N. R.
Publication year - 1998
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98ja01433
Subject(s) - heliosphere , field strength , physics , heliospheric current sheet , solar wind , solar cycle , magnetic field , interplanetary magnetic field , cosmic ray , astrophysics , solar cycle 24 , coronal mass ejection , field (mathematics) , solar minimum , latitude , variation (astronomy) , l shell , astronomy , earth's magnetic field , mathematics , quantum mechanics , pure mathematics
We discuss Voyager 1 (V1) observations of the heliospheric magnetic field strength from 1978 through 1996. During this period the distance of V1 from the Sun increased from ≈3 AU to 66 AU and its heliographic latitude increased from ≈5°S to 33°N. The magnetic field strength profile observed by V1 is consistent with Parker's spiral field model when one considers (1) the solar cycle variation of the observed magnetic field strength at 1 AU, B 1 ( t ) (which is a measure of the source field strength) and (2) the latitudinal and solar cycle variations of the solar wind speed, V ( t , θ). Both B 1 ( t ) and V( t , θ) make significant contributions to the variation of the magnetic field strength variations observed by V1. There is no evidence for a “magnetic flux deficit” increasing with distance from the Sun. There is a solar cycle variation of the magnetic field strength in the outer heliosphere, which will affect the modulation of cosmic rays.