ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O B-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: by allowing toroidal fields of opposite sign to exist on the two sides of the equator more easily. One way of capturing the physics of this in a 3D non-axisymmetric model may be to include a quenching of turbulent diffusivity in the regions of strong magnetic field. We plan to explore the effect of this in future. With these two opposite results at hand, one crucial question is: which of the two results is closer to reality? Although we cannot assert this with confidence at this stage, we believe that the 2D kinematic dynamo result that the dipolar parity is preferred on increasing diffusivity is the more appropriate result. Although in this paper we are taking account of the 3D nature of magnetic buoyancy and, in that sense, treating magnetic buoyancy more realistically, we still have not taken account of flux depletion from the convection zone and its bottom in an appropriate way. This is probably one important reason why our results are not matching with the results of previous 2D models (Chatterjee et al. 2004 ; Hotta Yokoyama 2010 ). We are right now exploring possible schemes to take account of the flux depletion due to magnetic buoyancy in a realistic way. We believe that this flux depletion is quite important in the solar dynamo. Choudhuri Hazra ( 2016 ) found that the Waldmeier effect cannot be reproduced from a theoretical dynamo model unless the flux depletion is taken into account. We have a future plan of incorporating flux loss due to magnetic buoyancy in a realistic way in our 3D kinematic dynamo model and then studying the parity issue more carefully. Since we are interested in a dynamo solution which has dipolar parity, we have converged on the reference solution presented here. If we decrease diffusivity, then we are led to the case where the meridional circulation provides the main transport mechanism for the poloidal field. On the other hand, if we increase diffusivity, then we obtain the quadrupolar mode. This is what has led us to choose the value 5 × 10 11 cm 2 s −1 for diffusivity inside the convection zone. 4. THE BUILD-UP OF THE POLAR FIELD After constructing the self-excited dynamo model, we now study how individual sunspot pairs contribute to the building up of the polar field and address the question of whether our understanding gained from this study necessitates the revision of some insights we have from SFT models. For this study, we shall put individual sunspot pairs on the solar surface by hand and look at the evolution of the magnetic field. In other words, we shall now not try to construct self-excited periodic solutions, although we shall keep using the same values of different parameters that we had used for constructing the self-excited periodic solution. We start our simulation by putting a single pair of bipolar sunspots in the northern hemisphere at different emergence angles λ emg and let it evolve under the axisymmetric mean flows and diffusion to see the development of the polar field. We have