Long term evolution of solar sector structure

Technical Report · Sun Dec 01 04:00:00 EST 1974

OSTI ID:7285819

Svalgaard, L; Wilcox, J M

The large-scale structure of the solar magnetic field during the past five sunspot cycles (representing by implication a much longer interval of time) was investigated using the polarity (toward or away from the sun) of the interplanetary magnetic field as inferred from polar geomagnetic observations. The polarity of the interplanetary magnetic field has previously been shown to be closely related to the polarity (into or out of the sun) of the large-scale solar magnetic field. It appears that a solar structure with four sectors per rotation persisted through the past five sunspot cycles, with a synodic rotation period near 27.0 days, and a small relative westward drift during the first half of each sunspot cycle and a relative eastward drift during the second half of each cycle. Superposed on this four-sector structure there is another structure with inward field polarity, a width in solar longitude of about 100 degrees and a synodic rotation period of about 28 to 29 days. This 28.5-day structure is usually most prominent during a few years near sunspot maximum. Some preliminary comparisons of these observed solar structures with theoretical considerations are given. (GRA)

• Research Organization: Stanford Univ., Calif. (USA). Inst. for Plasma Research
• OSTI ID: 7285819
• Report Number(s): AD/A-005896; SU-IPR-605
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DISTURBANCES
MAGNETIC FIELDS
POLARIZATION
SOLAR ACTIVITY
SOLAR CYCLE
STARS
SUN
SUNSPOTS