scholarly journals Characteristics of Substorm‐Onset‐Related and Non‐substorm Earthward Fast Flows and Associated Magnetic Flux Transport: THEMIS Observations

2021 ◽  
Author(s):  
Jinxing Li ◽  
Xiangning Chu ◽  
Jacob Bortnik ◽  
James Weygand ◽  
Chih‐Ping Wang ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Substorm Onset ◽  
Flux Transport

Magnetic Flux Transport on the Sun

Science ◽  
1989 ◽  
Vol 245 (4919) ◽  
pp. 712-718 ◽  
Author(s):  
Y. -M. WANG ◽  
A. G. NASH ◽  
N. R. SHEELEY
Keyword(s):  
Magnetic Flux ◽  
The Sun ◽  
Flux Transport

scholarly journals Impact of nonlinear surface inflows into activity belts on the solar dynamo

2020 ◽  
Vol 10 ◽  
pp. 62
Author(s):  
Melinda Nagy ◽  
Alexandre Lemerle ◽  
Paul Charbonneau
Keyword(s):  
Solar Cycle ◽  
Magnetic Flux ◽  
Activity Cycle ◽  
Surface Flux ◽  
Meridional Flow ◽  
Cycle Model ◽  
Flux Transport ◽  
Bona Fide ◽  
Nonlinear Surface ◽  
The Impact

We examine the impact of surface inflows into activity belts on the operation of solar cycle models based on the Babcock–Leighton mechanism of poloidal field regeneration. Towards this end we introduce in the solar cycle model of Lemerle & Charbonneau (2017. ApJ 834: 133) a magnetic flux-dependent variation of the surface meridional flow based on the axisymmetric inflow parameterization developped by Jiang et al. (2010. ApJ 717: 597). The inflow dependence on emerging magnetic flux thus introduces a bona fide nonlinear backreaction mechanism in the dynamo loop. For solar-like inflow speeds, our simulation results indicate a decrease of 10–20% in the strength of the global dipole building up at the end of an activity cycle, in agreement with earlier simulations based on linear surface flux transport models. Our simulations also indicate a significant stabilizing effect on cycle characteristics, in that individual cycle amplitudes in simulations including inflows show less scatter about their mean than in the absence of inflows. Our simulations also demonstrate an enhancement of cross-hemispheric coupling, leading to a significant decrease in hemispheric cycle amplitude asymmetries and temporal lag in hemispheric cycle onset. Analysis of temporally extended simulations also indicate that the presence of inflows increases the probability of cycle shutdown following an unfavorable sequence of emergence events. This results ultimately from the lower threshold nonlinearity built into our solar cycle model, and presumably operating in the sun as well.

Magnetic-flux transport by a convecting layer – topological, geometrical and compressible phenomena

1983 ◽  
Vol 132 ◽  
pp. 25-48 ◽  
Author(s):  
Wayne Arter
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Flux ◽  
Field Enhancement ◽  
Computer Code ◽  
Lower Half ◽  
Numerical Calculations ◽  
Flux Transport

Numerical calculations by Drobyshevski & Yuferev (1974) of the redistribution of magnetic flux by a Bénard layer with cells of square planform have been extended to higher values of electrical conductivity and to other velocity patterns, using a computer code developed for another purpose. Reconnection does not proceed as they supposed, but leads to overall field enhancement, and although the energy is greater at the bottom, there is as much unsigned flux in the upper half as in the lower half of the layer. However, compressible velocity patterns can concentrate flux at their bases.

Magnetic Flux Transport in the ISM through Turbulent Ambipolar Diffusion

2004 ◽  
pp. 45-51
Author(s):  
Fabian Heitsch ◽  
Ellen G. Zweibel ◽  
Adrianne D. Slyz ◽  
Julien E. G. Devriendt
Keyword(s):  
Magnetic Flux ◽  
Ambipolar Diffusion ◽  
Flux Transport

scholarly journals A Quantitative Study of Magnetic Flux Transport on the Sun

1983 ◽  
Vol 102 ◽  
pp. 273-278 ◽  
Author(s):  
N.R. Sheeley ◽  
J.P. Boris ◽  
T.R. Young ◽  
C.R. DeVore ◽  
K.L. Harvey
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Quantitative Study ◽  
Differential Rotation ◽  
Meridional Circulation ◽  
Diffusion Constant ◽  
The Sun ◽  
Flux Transport ◽  
Field Reversal ◽  
Best Fit

A computational model, based on diffusion, differential rotation, and meridional circulation, has been developed to simulate the transport of magnetic flux on the Sun. Using Kitt Peak magnetograms as input, we have determined a best-fit diffusion constant by comparing the computed and observed fields at later times. Our value of 730 ± 250 km2/s is consistent with Leighton's (1964) estimate of 770–1540 km2/s and is significantly larger than Mosher's (1977) estimate of 200–400 km2/s. This suggests that diffusion may be fast enough to account for the observed polar magnetic field reversal without requiring a significant assist from meridional currents.

scholarly journals Predicting cycle 24 using various dynamo-based tools

2008 ◽  
Vol 26 (2) ◽  
pp. 259-267 ◽  
Author(s):  
M. Dikpati
Keyword(s):  
Solar Cycle ◽  
Magnetic Flux ◽  
Active Regions ◽  
Flux Transport ◽  
Delayed Onset ◽  
Drift Speed ◽  
Sensitivity Tests ◽  
The Mean ◽  
Cycle 24

Abstract. Various dynamo-based techniques have been used to predict the mean solar cycle features, namely the amplitude and the timings of onset and peak. All methods use information from previous cycles, including particularly polar fields, drift-speed of the sunspot zone to the equator, and remnant magnetic flux from the decay of active regions. Polar fields predict a low cycle 24, while spot zone migration and remnant flux both lead to predictions of a high cycle 24. These methods both predict delayed onset for cycle 24. We will describe how each of these methods relates to dynamo processes. We will present the latest results from our flux-transport dynamo, including some sensitivity tests and how our model relates to polar fields and spot zone drift methods.

scholarly journals Modeling Coronal Response in Decaying Active Regions with Magnetic Flux Transport and Steady Heating

2017 ◽  
Vol 846 (2) ◽  
pp. 165 ◽  
Author(s):  
Ignacio Ugarte-Urra ◽  
Harry P. Warren ◽  
Lisa A. Upton ◽  
Peter R. Young
Keyword(s):  
Magnetic Flux ◽  
Active Regions ◽  
Flux Transport

Simulations of magnetic-flux transport in solar active regions

Solar Physics ◽  
1985 ◽  
Vol 102 (1-2) ◽  
pp. 41-49 ◽  
Author(s):  
C. R. DeVore ◽  
N. R. Sheeley ◽  
J. P. Boris ◽  
T. R. Young ◽  
K. L. Harvey
Keyword(s):  
Magnetic Flux ◽  
Active Regions ◽  
Flux Transport ◽  
Solar Active Regions
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