Magnetic Field Dependent Inflows towards Active Regions and Their Nonlinear Impact on a 3D Babcock-Leighton Solar Dynamo Model
The changing magnetic fields of the Sun are generated and maintained by a solar dynamo, the exact nature of which remains an unsolved fundamental problem in solar physics. Our objective is to investigate the role and impact of converging flows toward Bipolar Magnetic Regions (BMR inflows) on the Sun's global solar dynamo. These flows are large-scale physical phenomena that have been observed and so should be included in any comprehensive solar dynamo model. We have augmented the Surface flux Transport And Babcock-Leighton (STABLE) dynamo model to study the nonlinear feedback effect of BMR inflows with magnitudes varying with surface magnetic fields. This fully-3D realistic dynamo model produces the sunspot butterfly diagram and allows a study of the relative roles of dynamo saturation mechanisms such as tilt-angle quenching and BMR inflows. The results of our STABLE simulations show that magnetic field dependent BMR inflows significantly affect the evolution of the BMRs themselves and result in a reduced buildup of the global poloidal field due to local flux cancellation within the BMRs, to an extent that is sufficient to saturate the dynamo. As a consequence, for the first time, we have achieved fully 3D solar dynamo solutions in which BMR inflows alone regulate the amplitudes and periods of the magnetic cycles. Finally, we will discuss future work in which the magnetic field configuration of the solar corona is computed using the simulated photospheric magnetogram of the STABLE dynamo model.
Dr. Kinfe Teweldebirhan is an Assistant Professor at Aksum University. He got his PhD from Addis Ababa University (Astrophysics) in 2018, with Mark Miesch (NCAR/HAO) as his advisor. After that, he worked at Aksum University, Physics Department, teaching and mentoring graduate students. Currently he is a scientific visitor at NCAR/HAO. Kinfe has been working on the solar dynamo. He studies the nonlinear impact of converging flow into active regions (Bipolar Magnetic Regions) on the global solar magnetic activity of the sun in the framework of a three-dimensional Babcock-Leighton solar dynamo model. He is also currently working with Sarah Gibson at HAO in studying coronal magnetic field evolution using the simulated photospheric magnetic field of the sun from his dynamo models.