On the extended 23rd solar cycle

1Krivodubskij, VN, 2Cheremnykh, ОК
1Astronomical Observatory of the Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
2Space Research Institute of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, Kyiv, Ukraine
Kosm. nauka tehnol. 2011, 17 ;(1):23-28
Publication Language: Russian
An explanation of the mystery of the extended 23rd solar cycle duration about 13 years in the frame of αΩ-dynamo model is proposed. We took into account up-to-date observed data on the essential increase of averaged annual module of magnetic fields of large-scale sunspots β as well as the magnetic quenching for the a-effect which is connected with the observed fact and calculated by us. The period of a solar cycle in αΩ-dynamo model is defined by the expression Т'≈ 2π/{(1/2) /α∂Ω/ ∂r/}1/2, where α is the helicity parameter of turbulent pulsations, and ∂Ω/∂r is the radial gradient of the angular velocity in the convection zone of the Sun. The magnetic back reaction of the magnetic field β on the α-effect in the non-linear regime is described by the equation α(β) = α0 ψα(β), where α0 is the «nonmagnetic» value of the α-parameter, and ψα(β) ∞ β-3 is the decreasing (quenching) function.
       Ground-based observations testify that the average values of the magnetic field for large-scale sunspots В during the first half of the 23rd cycle were really higher (about 13 %) than during three last cycles. As a result of this, the value of the magnetic quenching-function ψαsp) in the 23rd cycle maximum was equal to about 70 percent of quenching-function value in the cycle minimum. This means that the α-parameter was magnetically quenched just in the same degree. Therefore, the calculated 23rd cycle dynamo-period is bound to increase by a factor of 1.2 and to be about 13 years.
Keywords: decreasing (quenching) function, dynamo-period, solar cycle
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