A Picture of Solar Minimum and the Onset of Solar Cycle 23. I. Global Magnetic Field Evolution

摘要: NSO/Kitt Peak synoptic charts of magnetic flux in the period from 1996 to 1998 are analyzed together with time series for 10.7 cm radio flux, sunspot number, and Mg II chromospheric index determine origin two times minimum activity study their relationships ascending phase solar cycle 23. The minima February-April September-November found correspond periods low southern northern hemispheres, respectively. new becomes dominant early 1997, but it is only summer 1997 that a significant increase can be detected fields observations as well irradiance data, by end 1998, level has increased value comparable one observed 1993. Using charts, we number persistent longitude bands active nests during this rising We find an zero three 1998. speculate these emergence pattern low-order modes instability type theoretical work Gilman, Fox, Dikpati on joint latitudinal differential rotation toroidal at base convection zone. argue consistent longitudinal wavenumber instabilities concentrated field tachocline discussed 1999 Gilman Dikpati.