On the Near-One-Year Variation of the Sun’s Mean Magnetic Field
- First Online:
- Cite this article as:
- Kotov, V.A. Sol Phys (2006) 239: 461. doi:10.1007/s11207-006-0146-x
- 52 Downloads
The mean magnetic field (MMF) of the Sun-as-a-star was measured over the last 38 years by six observatories (about 17 000 MMF daily records, 1968 – 2005). The MMF power spectrum reveals the presence of an enigmatic 1.029(7) year periodicity whose origin requires explanation. We show that this quasi-annual variation is not produced by modulation of the MMF signal due to the annual change of the Earth’s helio-latitude (one-year change of visibility of the Sun’s polar regions) as commonly accepted. The nature of this new solar phenomenon is open for discussion.