Magnetic Observations: During the Recent Declining Phase of Solar Activity

• Main Author: Edward J. Smith
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1995
• Subjects: South Pole; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.29.6829; http://jpltrs.jpl.nasa.gov/1995/95-0170.pdf

Changes in the magnetic field during the declining phase in solar activity are reviewed and compared with observations during past sunspot cycles. The stud y is based y on data obtained by IMP-8 and Ulysses. The field magnitude is found to have increased during the declining phase until it reached a maximum value of 11 in 1991.5, approximately two years after sunspot maximum. The dominant polarity of the field as by Ulysses from 1991.8 onward is consistent with the field of the sun's south pole which became negative after a reversal in early 1990. The sector structure disappeared at Ulysses in April 1993 when the latitude of the spacecraft was-300 revealing a low inclination of the current sheet. The solar wind structure evident in the magnetic field and plasma measurements shows a decline in the number and effectiveness of Coronal Mass Ejections. A large outburst of solar activity in 1991 caused 4 and numerous shocks at the location of Ulysses. Following a delay of more than a ye.