Rotation of the photospheric magnetic fields: A north-south asymmetry

Technical Report · Tue Aug 01 04:00:00 EDT 1989

OSTI ID:5096159

Antonucci, E; Hoeksema, J T; Scherrer, P H

During most of solar cycle 21, the large-scale photospheric field rotated more rapidly in the northern hemisphere than in the southern. The large-scale northern field rotated with a 26.9 day period (synodic), was centered at 15 degress N, and covered a latitude zone about 24 degrees wide. The large-scale southern field rotated with a periodicity of 28.1 days, was centered at 26 degrees S, and covered a latitude zone about 32 degrees wide. The authors analysis showed rotational power at only a few discrete latitudes and frequencies in each hemisphere. The center of each peak lies near the sunspot differential rotation curve. The largest scale field contributes to the configuration of the coronal and interplanetary magnetic field (IMF). The strength of the first harmonic of the northern field suggests that this structure may be related to the 4-sector pattern observed in the IMF polarity. The southern field had much lower power at the first harmonic of the solar rotation rate and so would contribute only to a 2-sector structure in the IMF. These results were discovered in Fourier analysis of photospheric synoptic charts obtained at the Wilcox Solar Observatory from 1976 - 1986 and confirmed a higher-resolution map from the National Solar Observatory. Mt. Wilson magnetic field measurements from solar cycle 20 show a similar north-south asymmetry.

• Research Organization: Stanford Univ., CA (USA). Center for Space Science and Astrophysics
• OSTI ID: 5096159
• Report Number(s): AD-A-213114/2/XAB; CSSA-ASTRO--89-14
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
ATMOSPHERES
DIFFERENTIAL GEOMETRY
FOURIER ANALYSIS
GEOMETRY
GRAPHS
INTERPLANETARY SPACE
MAGNETIC FIELDS
MAPS
MATHEMATICS
MOTION
PHOTOSPHERE
POWER
RESOLUTION
ROTATION
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR CYCLE
SPACE
STARSPOTS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
SUNSPOTS