Three-Dimensional Node Mapping Model for Toroidal Field Coils of Tokamak Physics Experiment System

2004 ◽  
Author(s):  
Wei Tong
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Three Dimensional ◽  
Transfer Effect ◽  
Toroidal Field ◽  
Poloidal Field ◽  
Experiment System ◽  
Mapping Model ◽  
Coil Winding ◽  
Physics Experiment

The toroidal field (TF) coils, along with the poloidal field (PF) coils, are used to produce the desirable magnetic field in a Tokamak Physics Experiment (TPX) system. To design a reliable and cryogenic stabilized system, heat generation and transport in these coils during normal TPX operation mush be carefully considered and analyzed. In order to accurately determine the temperature distribution in the TF coils, a three-dimensional node mapping model has been developed to deal with heat conduction between adjacent turns, pancakes, and case sidewalls. In such a way, the interactive heat transfer effect is taken into account in the design of TF magnets. The node mapping at the coil winding transitions is also integrated into the model.

scholarly journals Observing and modeling the poloidal and toroidal fields of the solar dynamo

2018 ◽  
Vol 609 ◽  
pp. A56 ◽  
Author(s):  
R. H. Cameron ◽  
T. L. Duvall ◽  
M. Schüssler ◽  
H. Schunker
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Time Lag ◽  
Solar Observatory ◽  
Toroidal Field ◽  
Solar Dynamo ◽  
Dynamo Model ◽  
Flux Emergence ◽  
Poloidal Field ◽  
Poloidal Magnetic Field

Context. The solar dynamo consists of a process that converts poloidal magnetic field to toroidal magnetic field followed by a process that creates new poloidal field from the toroidal field. Aims. Our aim is to observe the poloidal and toroidal fields relevant to the global solar dynamo and to see if their evolution is captured by a Babcock-Leighton dynamo. Methods. We used synoptic maps of the surface radial field from the KPNSO/VT and SOLIS observatories, to construct the poloidal field as a function of time and latitude; we also used full disk images from Wilcox Solar Observatory and SOHO/MDI to infer the longitudinally averaged surface azimuthal field. We show that the latter is consistent with an estimate of the longitudinally averaged surface azimuthal field due to flux emergence and therefore is closely related to the subsurface toroidal field. Results. We present maps of the poloidal and toroidal magnetic fields of the global solar dynamo. The longitude-averaged azimuthal field observed at the surface results from flux emergence. At high latitudes this component follows the radial component of the polar fields with a short time lag of between 1−3 years. The lag increases at lower latitudes. The observed evolution of the poloidal and toroidal magnetic fields is described by the (updated) Babcock-Leighton dynamo model.

scholarly journals High Resolution 3D Relativistic MHD Simulations of Jets

2009 ◽  
Vol 5 (H15) ◽  
pp. 254-255
Author(s):  
A. Ferrari ◽  
A. Mignone ◽  
P. Rossi ◽  
G. Bodo ◽  
S. Massaglia
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Full Length ◽  
Toroidal Field ◽  
Toroidal Magnetic Field ◽  
Mhd Simulations ◽  
Strong Current

AbstractWe performed high-resolution three dimensional numerical simulations of relativistic MHD jets carrying an initially toroidal magnetic field responsible for the process of jet acceleration and collimation. We find that in the 3D case the toroidal field gives rise to strong current driven kink instabilities leading to jet wiggling. However, it appears to be able to maintain an highly relativistic spine along its full length.

scholarly journals An Insight into the Solar Dynamo Theory

2017 ◽  
Vol 3 (1) ◽  
pp. 27-36
Author(s):  
Babu Ram Tiwari ◽  
Mukul Kumar
Keyword(s):  
Magnetic Field ◽  
Toroidal Field ◽  
Solar Dynamo ◽  
Dynamo Model ◽  
The Sun ◽  
Poloidal Field ◽  
Dynamo Theory ◽  
Dynamo Action ◽  
Flux Transport ◽  
Alpha Omega

The Sun manifests its magnetic field in form of the solar activities, being observed on the surface of the Sun. The dynamo action is responsible for the evolution of the magnetic field in the Sun. The present article aims to present an overview of the studies have been carried on the theory and modelling of the solar dynamo. The article describes the alpha-omega dynamo model. Generally, the dynamo model involves the cyclic conversion between the poloidal field and the toroidal field. In case of alpha-omega dynamo model, the strong differential rotation generates a toroidal field near the base of the convection zone. On the other hand, the turbulent helicity leads to the generation of the poloidal field near the surface. The turbulent diffusion and the meridional circulation are considered as the two important flux transport agents in this model. The article briefly describes the theory of solar dynamo and mean field dynamo model.

Thermal Transport in Laminar Convective Flow of Ferrofluids in the Presence of External Magnetic Field

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Ram Krishna Shah ◽  
Jai Kumar Drave ◽  
Sameer Khandekar
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Reynolds Number ◽  
Magnetic Force ◽  
Three Dimensional ◽  
Inertial Force ◽  
Flow Reynolds Number ◽  
Downstream Flow ◽  
Laminar Forced Convection ◽  
Upstream Flow

Abstract A three-dimensional (3D) numerical investigation is carried out to examine the effect of magnetic field (MF) on laminar forced convection of ferrofluids. Laminar flow (Reynolds number (Re) ≤ 100) of ferrofluid is modeled in a square mini-channel of 2 mm hydraulic diameter in the presence of the MF. A magnetic force is induced in ferrofluids because of the applied MF, which accelerates the upstream flow and decelerates the downstream flow with respect to the magnet's location. The acceleration/deceleration of the flow disrupts the hydrodynamic and thermal boundary layers (BLs), positively affecting the heat transfer. The extent of magnetic influence primarily depends on the Reynolds number and induced magnetic force. At low Re (= 25), where magnetic force dominates over inertial force, the flow of ferrofluid is strongly affected by the MF. This results in a higher augmentation in convective heat transfer. As the Re of the flow is increased to Re = 75, the inertial forces partially overcome the effect of the magnetic force, resulting in a smaller augmentation. The interaction of magnetic and inertia forces is expressed through a dimensionless magnetic Froude number (Frm). The effect of volumetric concentration of nanoparticles, Reynolds number, and the presence of multiple magnets placed along the flow channel on heat transfer is investigated through a parametric study. A correlation has also been proposed to predict the net enhancement in the Nusselt number due to the application of the MF based on the results of the present study.

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