scholarly journals Nonlinear MHD simulation of core plasma collapse events in Wendelstein 7-X

2021 ◽  
Author(s):  
Yasuhiro Suzuki ◽  
Shimpei Futatani ◽  
Joachim Geiger
Keyword(s):  
Current Density ◽  
Three Dimensional ◽  
Plasma Pressure ◽  
Core Collapse ◽  
Nonlinear Coupling ◽  
Mode Structure ◽  
The Core ◽  
Core Plasma ◽  
Plasma Core ◽  
Rotational Transform

Abstract Three-dimensional nonlinear MHD simulations study the core collapse events observed in a stellarator experiment, Wendelstein 7-X. In the low magnetic shear configuration like the Wendelstein 7-X, the rotational transform profile is very sensitive to the toroidal current density. The 3D equilibrium with localized toroidal current density is studied. If the toroidal current density follows locally in the middle of the minor radius, the rotational transform is also changed locally. Sometimes, the magnetic topology changes due to appearing the magnetic island. A full three-dimensional nonlinear MHD code studies the nonlinear behaviors of the MHD instability. It was found that the following sequence. At first, the high-n ballooning-type mode structure appears in the plasma core, and then the mode linearly grows. The high-n ballooning modes nonlinearly couple and saturate. The mode structure changes to the low-n mode. The magnetic field structure becomes strongly stochastic into the plasma core due to the nonlinear coupling in that phase. Finally, the plasma pressure diffuses along the stochastic field lines, and then the core plasma pressure drops. This is a crucial result to interpret the core collapse event by strong nonlinear coupling.

scholarly journals Three-dimensional models of core-collapse supernovae from low-mass progenitors with implications for Crab

2020 ◽  
Vol 496 (2) ◽  
pp. 2039-2084 ◽  
Author(s):  
G Stockinger ◽  
H-T Janka ◽  
D Kresse ◽  
T Melson ◽  
T Ertl ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Iron Core ◽  
Core Collapse ◽  
Crab Pulsar ◽  
Core Collapse Supernova ◽  
Spin Period ◽  
The Core ◽  
Low Mass ◽  
Catch Up ◽  
Three Dimensional Models

ABSTRACT We present 3D full-sphere supernova simulations of non-rotating low-mass (∼9 M⊙) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions (∼0.5–1.0 × 1050 erg) of iron-core progenitors at the low-mass end of the core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB) progenitor with an oxygen–neon–magnesium core that collapses and explodes as electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN models is modelled self-consistently using the vertex-prometheus code, whereas the ECSN explosion is modelled using parametric neutrino transport in the prometheus-HOTB code, choosing different explosion energies in the range of previous self-consistent models. The sAGB and LMCCSN progenitors that share structural similarities have almost spherical explosions with little metal mixing into the hydrogen envelope. A LMCCSN with less second dredge-up results in a highly asymmetric explosion. It shows efficient mixing and dramatic shock deceleration in the extended hydrogen envelope. Both properties allow fast nickel plumes to catch up with the shock, leading to extreme shock deformation and aspherical shock breakout. Fallback masses of $\mathord {\lesssim }\, 5\, \mathord {\times }\, 10^{-3}$ M⊙ have no significant effects on the neutron star (NS) masses and kicks. The anisotropic fallback carries considerable angular momentum, however, and determines the spin of the newly born NS. The LMCCSN model with less second dredge-up results in a hydrodynamic and neutrino-induced NS kick of >40 km s−1 and a NS spin period of ∼30 ms, both not largely different from those of the Crab pulsar at birth.

scholarly journals One-, Two-, and Three-dimensional Simulations of Oxygen-shell Burning Just before the Core Collapse of Massive Stars

2019 ◽  
Vol 881 (1) ◽  
pp. 16 ◽  
Author(s):  
Takashi Yoshida ◽  
Tomoya Takiwaki ◽  
Kei Kotake ◽  
Koh Takahashi ◽  
Ko Nakamura ◽  
...  
Keyword(s):  
Massive Stars ◽  
Three Dimensional ◽  
Core Collapse ◽  
The Core ◽  
Three Dimensional Simulations

Rapidly Rotating Core-Collapse Models

1985 ◽  
Vol 6 (2) ◽  
pp. 214-216
Author(s):  
M. C. Thompson
Keyword(s):  
Three Dimensional ◽  
Computer Time ◽  
Rotational Energy ◽  
Gravitational Energy ◽  
Numerical Code ◽  
Core Collapse ◽  
The Core ◽  
Collapse Models ◽  
Three Dimensional Models ◽  
Axisymmetric Instability

AbstractVery few (if any at all) three dimensional models of the final evolutionary stages of a star’s life have appeared in the literature. Such models may be important if the stellar core maintains sufficient rotational energy during it’s lifetime so that when collapse finally occurs, the increase of rotational energy to gravitational energy, may lead to a non-axisymmetric instability.A sequence of core collapse models with decreasing rotation rate is considered. These models were calculated using a three dimensional, post-Newtonian, hydrodynamical, numerical code. The results show that for high precollapse rotational energies the core can become unstable resulting in the formation of what resemble ‘spiral arms’. Unfortunately, because of limits on computer time, the calculations had to be discontinued shortly after this development occurred.

Three-dimensional porous copper-decorated bismuth-based nanofoam for boosting electrochemical reduction of CO2 to formate

2021 ◽  
Author(s):  
Yingchun Zhang ◽  
Changsheng Cao ◽  
Xintao Wu ◽  
Qi-Long Zhu
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Three Dimensional ◽  
Co2 Reduction ◽  
Reduction Reaction ◽  
High Current ◽  
Porous Copper ◽  
Reduction Of Co2 ◽  
Co2 Reduction Reaction ◽  
Wide Potential

Bismuth (Bi)-based nanomaterials are considered as the promising electrocatalysts for electrocatalytic CO2 reduction reaction (CO2RR), but it is challenging to achieve high current density and selectivity in a wide potential...

scholarly journals Dynamical Evolution of Globular Clusters After Core Collapse

1985 ◽  
Vol 113 ◽  
pp. 139-160 ◽  
Author(s):  
Douglas C. Heggie
Keyword(s):  
Surface Density ◽  
Globular Clusters ◽  
Stellar System ◽  
Dynamical Evolution ◽  
Theoretical Models ◽  
Numerical Calculations ◽  
Core Collapse ◽  
Density Profiles ◽  
The Core ◽  
Fokker Planck

This review describes work on the evolution of a stellar system during the phase which starts at the end of core collapse. It begins with an account of the models of Hénon, Goodman, and Inagaki and Lynden-Bell, as well as evaporative models, and modifications to these models which are needed in the core. Next, these models are related to more detailed numerical calculations of gaseous models, Fokker-Planck models, N-body calculations, etc., and some problems for further work in these directions are outlined. The review concludes with a discussion of the relation between theoretical models and observations of the surface density profiles and statistics of actual globular clusters.

scholarly journals Observations on the W-transport in the core plasma of JET and ASDEX Upgrade

2013 ◽  
Vol 55 (12) ◽  
pp. 124036 ◽  
Author(s):  
T Pütterich ◽  
R Dux ◽  
R Neu ◽  
M Bernert ◽  
M N A Beurskens ◽  
...  
Keyword(s):  
The Core ◽  
Core Plasma

The three-dimensional structure of interleukin-1β

1988 ◽  
Vol 16 (6) ◽  
pp. 949-953 ◽  
Author(s):  
JOHN P. PRIESTLE ◽  
HANS-PETER SCHÄR ◽  
MARKUS G. GRÜTTER
Keyword(s):  
Polypeptide Chain ◽  
Three Dimensional ◽  
Interleukin 1Β ◽  
Dimensional Structure ◽  
X Ray ◽  
Three Dimensional Structure ◽  
R Factor ◽  
The Core ◽  
Internal Sequence ◽  
Network Of Hydrogen Bonds

Summary The three-dimensional structure of human recombinant interleukin-1β has been determined at 0.24 nm resolution by X-ray crystallographic techniques. The partially refined model has a crystallographic R-factor of just under 19%. The structure is composed of 12 β-strands forming a complex network of hydrogen bonds. The core of the structure can best be described as a tetrahedron whose edges are each formed by two antiparallel β-strands. The interior of this structure is filled with hydrophobic side-chains. There is a 3-fold repeat in the folding of the polypeptide chain. Although this folding pattern suggests gene triplication, no significant internal sequence homology between topologically corresponding residues exists. The folding topology of interleukin-1β is very similar to that described by A. D. McLachlan [(1979) J. Mol. Biol. 133, 557–563] for soybean trypsin inhibitor.

Physics analyses on the core plasma properties in the helical fusion DEMO reactor FFHR-d1

2014 ◽  
Vol 54 (4) ◽  
pp. 043010 ◽  
Author(s):  
J. Miyazawa ◽  
Y. Suzuki ◽  
S. Satake ◽  
R. Seki ◽  
Y. Masaoka ◽  
...  
Keyword(s):  
Plasma Properties ◽  
The Core ◽  
Core Plasma
Sign in / Sign up

Export Citation Format

Share Document