Numerical simulations of electromagnetic behavior and AC loss in rectangular bulk superconductor with an elliptical flaw under AC magnetic fields

Cryogenics ◽  
2015 ◽  
Vol 69 ◽  
pp. 1-9 ◽  
Author(s):  
Jing Xia ◽  
Youhe Zhou
Keyword(s):  
Magnetic Fields ◽  
Numerical Simulations ◽  
Ac Loss ◽  
Bulk Superconductor ◽  
Electromagnetic Behavior

Recollimation shocks in relativistic jets

2018 ◽  
Vol 27 (10) ◽  
pp. 1844011 ◽  
Author(s):  
José M. Martí ◽  
Manel Perucho ◽  
José L. Gómez ◽  
Antonio Fuentes
Keyword(s):  
Magnetic Fields ◽  
Numerical Simulations ◽  
Theoretical Background ◽  
Synchrotron Emission ◽  
Relativistic Jets ◽  
Dominant Type ◽  
X Ray ◽  
Extragalactic Jets ◽  
X Ray Binaries ◽  
Selection Of

Recollimation shocks (RS) appear associated with relativistic flows propagating through pressure mismatched atmospheres. Astrophysical scenarios invoking the presence of such shocks include jets from AGNs and X-ray binaries and GRBs. We shall start reviewing the theoretical background behind the structure of RS in overpressured jets. Next, basing on numerical simulations, we will focus on the properties of RS in relativistic steady jets threaded by helical magnetic fields depending on the dominant type of energy. Synthetic radio maps from the simulation of the synchrotron emission for a selection of models in the context of parsec-scale extragalactic jets will also be discussed.

scholarly journals Multiscale structures and noise in magnetized plasmas line-tied at conducting surfaces

2019 ◽  
Vol 85 (2) ◽  
Author(s):  
A. B. Hassam ◽  
Yi-Min Huang
Keyword(s):  
Magnetic Fields ◽  
Boundary Conditions ◽  
Numerical Simulations ◽  
Magnetized Plasma ◽  
Long Wavelength ◽  
Numerical Noise ◽  
Long Time ◽  
Multiscale Structures ◽  
Ideal Magnetohydrodynamic ◽  
Numerical And Analytical Methods

In magnetized plasma situations where magnetic fields intersect massive conducting boundaries, ‘line-tied’ boundary conditions are often used, analytically and in numerical simulations. For ideal magnetohydrodynamic (MHD) plasmas, these conditions are arrived at given the relatively long time scales for magnetic fields penetrating resistively into good conductors. Under line-tied boundary conditions, numerical simulations often exhibit what could be construed as numerical ‘noise’ emanating from the boundaries. We show here that this ‘noise’ is real. By combining numerical and analytical methods, we highlight the existence of sharp spatial structures near the conductors and confirm the appearance of short wavelength structures riding on long wavelength modes. We conclude that, for numerical fidelity, the short multiscale structures need to be resolved. Generally, the short structure widths scale as the square root of the plasma $\unicode[STIX]{x1D6FD}$.

Magnetic fields end-face effect investigation of HTS bulk over PMG with 3D-modeling numerical method

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542041
Author(s):  
Yujie Qin ◽  
Yiyun Lu
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Numerical Method ◽  
3D Modeling ◽  
Field Vector ◽  
Vector Method ◽  
Hts Bulk ◽  
Levitation System ◽  
Electromagnetic Behavior ◽  
The Magnetic Field

In this paper, the magnetic fields end-face effect of high temperature superconducting (HTS) bulk over a permanent magnetic guideway (PMG) is researched with 3D-modeling numerical method. The electromagnetic behavior of the bulk is simulated using finite element method (FEM). The framework is formulated by the magnetic field vector method (H-method). A superconducting levitation system composed of one rectangular HTS bulk and one infinite long PMG is successfully investigated using the proposed method. The simulation results show that for finite geometrical HTS bulk, even the applied magnetic field is only distributed in [Formula: see text]–[Formula: see text] plane, the magnetic field component Hz which is along the [Formula: see text]-axis can be observed interior the HTS bulk.

AC loss intrinsic to MgB2 at low magnetic fields

2005 ◽  
Vol 18 (3) ◽  
pp. 307-310 ◽  
Author(s):  
Roland V Sarmago ◽  
Margie P Olbinado
Keyword(s):  
Magnetic Fields ◽  
Ac Loss

scholarly journals Historical perspective on astrophysical MHD simulations

2010 ◽  
Vol 6 (S270) ◽  
pp. 7-17
Author(s):  
Michael L. Norman
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Historical Development ◽  
Adaptive Mesh Refinement ◽  
Historical Perspective ◽  
Adaptive Mesh ◽  
Personal Perspective ◽  
Mhd Simulations

AbstractThis contribution contains the introductory remarks that I presented at IAU Symposium 270 on “Computational Star Formation” held in Barcelona, Spain, May 31–June 4, 2010. I discuss the historical development of numerical MHD methods in astrophysics from a personal perspective. The recent advent of robust, higher-order accurate MHD algorithms and adaptive mesh refinement numerical simulations promises to greatly improve our understanding of the role of magnetic fields in star formation.

Numerical simulations of liquid metal experiments on cosmic magnetic fields

2009 ◽  
Vol 23 (6) ◽  
pp. 405-429 ◽  
Author(s):  
Frank Stefani ◽  
André Giesecke ◽  
Gunter Gerbeth
Keyword(s):  
Magnetic Fields ◽  
Liquid Metal ◽  
Numerical Simulations

Improved experimental set-up for calorimetric AC loss measurements on HTSs carrying transport currents in applied magnetic fields at variable temperatures

2001 ◽  
Vol 354 (1-4) ◽  
pp. 197-201 ◽  
Author(s):  
N. Magnusson ◽  
N. Schönborg ◽  
A. Wolfbrandt ◽  
S. Hörnfeldt
Keyword(s):  
Magnetic Fields ◽  
Ac Loss ◽  
Set Up

scholarly journals Numerical study of jets produced by conical wire arrays on the Magpie pulsed power generator

2010 ◽  
Vol 6 (S274) ◽  
pp. 429-432
Author(s):  
Matteo Bocchi ◽  
Jerry P. Chittenden ◽  
Andrea Ciardi ◽  
Francisco Suzuki-Vidal ◽  
Gareth N. Hall ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Pulsed Power ◽  
Astrophysical Jets ◽  
Power Generator ◽  
Wire Arrays ◽  
Pulsed Power Generator

AbstractWith the aim to model jets produced by conical wire arrays on the MAGPIE generator, and to strengthen the link between laboratory and astrophysical jets, we performed three-dimensional magneto-hydro-dynamic numerical simulations using the code GORGON and successfully reproduced the experiments. We found that a minimum resolution of ~100 μm is required to retrieve the unstable character of the jet. Moreover, arrays with less wires produce more unstable jets with stronger magnetic fields around them.

scholarly journals The Effect of Small Scale Motion on an Essentially-Nonlinear Dynamo

2010 ◽  
Vol 6 (S271) ◽  
pp. 367-368
Author(s):  
Benjamin M. Byington ◽  
Nicholas H. Brummell ◽  
Steven M. Tobias
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Small Scale ◽  
Local Velocity ◽  
Dissipative Effects ◽  
Dynamo Mechanism ◽  
New Type ◽  
Scale Motion

AbstractA dynamo is a process by which fluid motions sustain magnetic fields against dissipative effects. Dynamos occur naturally in many astrophysical systems. Theoretically, we have a much more robust understanding of the generation and maintenance of magnetic fields at the scale of the fluid motions or smaller, than that of magnetic fields at scales much larger than the local velocity. Here, via numerical simulations, we examine one example of an “essentially nonlinear” dynamo mechanism that successfully maintains magnetic field at the largest available scale (the system scale) without cascade to the resistive scale. In particular, we examine whether this new type of dynamo at the system scale is still effective in the presence of other smaller-scale dynamics (turbulence).

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