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McCloughan, John; Durrant, C. J.

doi:10.1023/a:1022400324489

Cited by 15 publications

(7 citation statements)

References 25 publications

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“…They found excellent agreement and showed that predictions of polar field reversals and the polar field strength at cycle minimum could be made years in advance. McCloughan and Durrant (2002) and Durrant and McCloughan (2004) noted that flux transport produces and requires synchronic maps rather than traditional synoptic maps and care must therefore be taken when estimating transport parameters from synoptic maps. Yeates et al (2007) used synoptic magnetogram data as the initial condition and assimilated the emergence of new active regions into the model throughout the course of the simulation to maintain the accuracy of the simulated photospheric magnetic field over many months.…”

Section: Assimilations Of Observed Magnetogramsmentioning

confidence: 99%

Magnetic Flux Transport at the Solar Surface

et al. 2014

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After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One is that the surface field, and its dynamics, sets the boundary condition for the coronal and heliospheric magnetic fields. Another is that the surface evolution gives us insight into the dynamo process. In particular, it plays an essential role in the Babcock-Leighton model of the solar dynamo. Describing this evolution is the aim of the surface flux transport model. The model starts from the emergence of magnetic bipoles. Thereafter, the model is based on the induction equation and the fact that after emergence the magnetic field is observed to evolve as if it were purely The induction equation then describes how the surface flows -differential rotation, meridional circulation, granular, supergranular flows, and active region inflows -determine the evolution of the field (now taken to be purely radial). In this paper, we review the modeling of the various processes that determine the evolution of the surface field. We restrict our attention to their role in the surface flux transport model. We also discuss the success of the model and some of the results that have been obtained using this model.

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Section: Assimilations Of Observed Magnetogramsmentioning

confidence: 99%

Magnetic Flux Transport at the Solar Surface

et al. 2014

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“…On the Sun the timescale for differential rotation to act is τ dr = 2π/(Ω(0) − Ω( 90)) ∼ 1/4 year. Within magnetic flux transport simulations the profile ( 2) is either applied directly, simulating the actual rotation of the Sun, or with the Carrington rotation rate (13.2 deg/day) subtracted (van Ballegooijen et al, 1998;McCloughan and Durrant, 2002).…”

Section: Standard Modelmentioning

confidence: 99%

The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models

Mackay

Yeates

2012

Living Rev. Solar Phys.

221

181

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In this review, our present day understanding of the Sun's global photospheric and coronal magnetic fields is discussed from both observational and theoretical viewpoints. Firstly, the large-scale properties of photospheric magnetic fields are described, along with recent advances in photospheric magnetic flux transport models. Following this, the wide variety of theoretical models used to simulate global coronal magnetic fields are described. From this, the combined application of both magnetic flux transport simulations and coronal modeling techniques to describe the phenomena of coronal holes, the Sun's open magnetic flux and the hemispheric pattern of solar filaments is discussed. Finally, recent advances in non-eruptive global MHD models are described. While the review focuses mainly on solar magnetic fields, recent advances in measuring and modeling stellar magnetic fields are described where appropriate. In the final section key areas of future research are identified.

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“…This creates a problem when a simultaneous map is needed at all longitudes, as is required for the initial condition in the global simulation. McCloughan and Durrant (2002) deal with the problem by using a synoptic evolution equation, rather than the flux transport equation itself. We take an alternative approach and produce an initial configuration directly from the magnetogram.…”

Section: Magnetogram Data and Initial Surface Distributionmentioning

confidence: 99%

Modelling the Global Solar Corona: Filament Chirality Observations and Surface Simulations

2007

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Abstract.The hemispheric pattern of solar filaments is considered in the context of the global magnetic field of the solar corona. In recent work Mackay and van Ballegooijen have shown how, for a pair of interacting magnetic bipoles, the observed chirality pattern could be explained by the dominant range of bipole tilt angles and helicity in each hemisphere. This study aims to test this earlier result through a direct comparison between theory and observations, using newly-developed simulations of the actual surface and 3D coronal magnetic fields over a 6-month period, on a global scale.In this paper we consider two key components of the study; firstly the observations of filament chirality for the sample of 255 filaments, and secondly our new simulations of the large-scale surface magnetic field. Based on a flux-transport model, these will be used as the lower boundary condition for the future 3D coronal simulations. Our technique differs significantly from those of other authors, where the coronal field is either assumed to be purely potential, or has to be reset back to potential every 27 days in order that the photospheric field remain accurate. In our case we ensure accuracy by the insertion of newly-emerging bipolar active regions, based on observed photospheric synoptic magnetograms. The large-scale surface field is shown to remain accurate over the 6-month period, without any resetting. This new technique will enable future simulations to consider the long-term build-up and transport of helicity and shear in the coronal magnetic field, over many months or years.

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Cited by 15 publications

References 25 publications

Magnetic Flux Transport at the Solar Surface

Magnetic Flux Transport at the Solar Surface

The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models

Modelling the Global Solar Corona: Filament Chirality Observations and Surface Simulations

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