Numerical simulations of fast ion loss measurements induced by magnetic islands in the ASDEX Upgrade tokamak

2009 ◽  
Vol 49 (9) ◽  
pp. 095021 ◽  
Author(s):  
M. Gobbin ◽  
L. Marrelli ◽  
H.U. Fahrbach ◽  
M. Garcia-Muñoz ◽  
S. Günter ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Magnetic Islands ◽  
Fast Ion

scholarly journals Nonlinear dynamics of turbulence driven magnetic islands. II. Numerical simulations

2017 ◽  
Vol 24 (4) ◽  
pp. 042309 ◽  
Author(s):  
O. Agullo ◽  
M. Muraglia ◽  
S. Benkadda ◽  
A. Poyé ◽  
N. Dubuit ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Numerical Simulations ◽  
Magnetic Islands

scholarly journals Comparison of fast ion collective Thomson scattering measurements at ASDEX Upgrade with numerical simulations

2010 ◽  
Vol 50 (3) ◽  
pp. 035012 ◽  
Author(s):  
M. Salewski ◽  
F. Meo ◽  
M. Stejner ◽  
O. Asunta ◽  
H. Bindslev ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Thomson Scattering ◽  
Scattering Measurements ◽  
Collective Thomson Scattering ◽  
Fast Ion

Development of a reduced model for energetic particle transport by sawteeth in tokamaks

2021 ◽  
Author(s):  
Mario Podesta ◽  
Marina Gorelenkova ◽  
Nikolai N Gorelenkov ◽  
Roscoe B White ◽  
Phillip Bonofiglo ◽  
...  
Keyword(s):  
Numerical Models ◽  
Transport Coefficients ◽  
Energetic Particles ◽  
Reduced Model ◽  
Magnetic Islands ◽  
Ion Distribution ◽  
Tearing Modes ◽  
Plasma Species ◽  
Energetic Particle Transport ◽  
Fast Ion

Abstract The sawtooth instability is known for inducing transport and loss of energetic particles (EP), and for generating seed magnetic islands that can trigger tearing modes. Both effects degrade the overall plasma performance. Several theories and numerical models have been previously developed to quantify the expected EP transport caused by sawteeth, with various degrees of sophistication to differentiate the response of EPs at different energies and on different orbits (e.g. passing vs. trapped), although the analysis is frequently limited to a single time slice during a tokamak discharge. This work describes the development and initial benchmark of a framework that enables a reduced model for EP transport by sawteeth retaining the full EP phase-space information. The model, implemented in the ORBIT hamiltonian particle-following code, can be used either as a standalone post-processor taking input data from codes such as TRANSP, or as a preprocessor to compute transport coefficients that can be fed back to TRANSP for time-dependent simulations including the effects of sawteeth on energetic particles. The advantage of the latter approach is that the evolution of the EP distribution can be simulated quantitatively for sawtoothing discharges, thus enabling a more accurate modeling of sources, sinks and overall transport properties of EP and thermal plasma species for comprehensive physics studies that require detailed information of the fast ion distribution function and its evolution over time.

Numerical study of fast ion behavior in the presence of magnetic islands and toroidal field ripple in the EAST tokamak

2014 ◽  
Vol 23 (10) ◽  
pp. 105201
Author(s):  
Wei Zhang ◽  
Li-Qun Hu ◽  
You-Wen Sun ◽  
Si-Ye Ding ◽  
Zi-Jun Zhang ◽  
...  
Keyword(s):  
Numerical Study ◽  
Toroidal Field ◽  
Magnetic Islands ◽  
Toroidal Field Ripple ◽  
Fast Ion

scholarly journals Evidence of transient reconnection in the outflow jet of primary reconnection site

2014 ◽  
Vol 32 (3) ◽  
pp. 239-248 ◽  
Author(s):  
R. Wang ◽  
R. Nakamura ◽  
T. Zhang ◽  
A. Du ◽  
W. Baumjohann ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Observational Evidence ◽  
Generation Mechanism ◽  
Magnetic Islands ◽  
Magnetic Island ◽  
Subsequent Evolution ◽  
Reconnection Site

Abstract. The precise mechanism for the formation of magnetic islands in the magnetotail and the subsequent evolution are still controversial. New investigations have provided the first observational evidence of secondary reconnection in the earthward outflow jet of primary reconnection in the magnetotail. The secondary reconnection takes place 38 c/ωpi earthward from the primary reconnection site and results in the birth of a magnetic island observed. This generation mechanism is different from the widely used model of multiple reconnection X-lines. The duration of the secondary reconnection was approximate one ion gyration period (5 s). The observations resemble recent numerical simulations where magnetic reconnection could spontaneously and transiently happen in the outflow jet, called secondary reconnection, which was used to explain the formation of the dipolarization fronts. Coincidentally, another magnetic island moving earthward passed through three satellites successively. By this chance we find the magnetic island was accelerated towards Earth with an acceleration of about 9 km s−2 at −19 RE in the magnetotail.

Numerical simulations of NBI fast ion loss with RMPs on the EAST tokamak

2020 ◽  
Vol 60 (8) ◽  
pp. 086013
Author(s):  
Yingfeng Xu ◽  
Li Li ◽  
Youjun Hu ◽  
Yueqiang Liu ◽  
Wenfeng Guo ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Fast Ion

Saturation of magnetic islands in equilibria with a finite current gradient. Part II: numerical simulations

2014 ◽  
Vol 56 (12) ◽  
pp. 125005 ◽  
Author(s):  
A Poyé ◽  
A I Smolyakov ◽  
O Agullo ◽  
S Benkadda ◽  
X Garbet
Keyword(s):  
Numerical Simulations ◽  
Magnetic Islands

scholarly journals MHD Numerical Simulations of Magnetic Reconnection Associated with Emerging Flux

1993 ◽  
Vol 141 ◽  
pp. 500-503
Author(s):  
K. Shibata ◽  
S. Nozawa ◽  
R. Matsumoto
Keyword(s):  
Magnetic Field ◽  
Numerical Simulations ◽  
Magnetic Reconnection ◽  
Coronal Magnetic Field ◽  
Two Dimensional ◽  
Magnetic Islands ◽  
X Ray ◽  
Hot Plasma ◽  
Mass Ejection ◽  
Coronal Field

AbstractTwo-dimensional (2D) magnetohydrodynamic (MHD) numerical simulations have been performed to study magnetic reconnection between emerging flux and the overlying coronal magnetic field, taking into account of gravity. It is found that (1) reconnection starts when most of chromospheric mass in the current sheet between the emerging flux and the coronal field has drained down along the loop because of gravity, (2) multiple magnetic islands, which confine cool, dense chromospheric plasma, are created in the sheet; the islands coalesce dynamically and are ejected along the sheet, together with the ambient hot plasma, at Alfven speed. The coexistence of hot and cool plasmas in the mass ejection (jet) associated with the reconnection seems to explain those X-ray jets observed by Yohkoh, which are identified with Hα surges.

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