Observations of the magnetic fields in the polar regions of the Sun are presented for the period 1960-1971. At the start of this interval the fields atthe two poles were consistently of opposite sign and averaged around 1 G. Early in 1961 the field in the south decreased suddenly and the field in th
The strength of the Sun's polar fields
โ Scribed by Leif Svalgaard; Thomas L. Duvall; Philip H. Scherrer
- Publisher
- Springer
- Year
- 1978
- Tongue
- English
- Weight
- 671 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0038-0938
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โฆ Synopsis
The magnetic field strength within the polar caps of the Sun is an important parameter for both the solar activity cycle and for our understanding of the interplanetary magnetic field. Measurements of the line-of-sight component of the magnetic field generally yield 0.1 to 0.2 mT near times of sunspot minimum. In this paper we report measurements of the polar fields made at the Stanford Solar Observatory using the Fe t line A 525.02 nm. We find that the average flux density poleward of 55 ~ latitude is about 0.6 mT peaking to more than 1 mT at the pole and decreasing to 0.2 mT at the polar cap boundary. The total open flux through either polar cap thus becomes about 3 x 10 TM Wb. We also show that observed magnetic field strengths vary as the line-of-sight component of nearly radial fields.
๐ SIMILAR VOLUMES
Regarding new bipolar magnetic regions as sources of flux, we have simulated the evolution of the radial component of the solar photospheric magnetic field during 1976-1984 and derived the corresponding evolution of the line-of-sight polar fields as seen from Earth. The observed timing and strength
Poleward migration of the magnetic neutral line on the Sun has been calculated for the periods 1945-1950 and 1955-1981 using synoptic charts based on Hc~ observations. Epochs of sign reversal of the solar magnetic field at latitudes 50 ~ to 90 ~ have been determined for these periods. During the cyc
Poleward migration of the magnetic neutral line on the Sun has been computed for the period 1904-1940 using synoptic charts based on Hot observations and the epochs of sign reversal of the solar magnetic field at latitudes 50 ~ to 90 ~ have been determined for this period. During the cycles 16 and 1
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