Bootstrap current control studies in the Wendelstein 7-X stellarator using the free-plasma-boundary version of the SIESTA MHD equilibrium code

2018 ◽  
Vol 60 (2) ◽  
pp. 025023 ◽  
Author(s):  
H Peraza-Rodriguez ◽  
J M Reynolds-Barredo ◽  
R Sanchez ◽  
V Tribaldos ◽  
J Geiger
Keyword(s):  
Plasma Boundary ◽  
Current Control ◽  
Mhd Equilibrium ◽  
Bootstrap Current ◽  
Boundary Version ◽  
Free Plasma

scholarly journals Extension of the SIESTA MHD equilibrium code to free-plasma-boundary problems

2017 ◽  
Vol 24 (8) ◽  
pp. 082516 ◽  
Author(s):  
H. Peraza-Rodriguez ◽  
J. M. Reynolds-Barredo ◽  
R. Sanchez ◽  
J. Geiger ◽  
V. Tribaldos ◽  
...  
Keyword(s):  
Plasma Boundary ◽  
Boundary Problems ◽  
Mhd Equilibrium ◽  
Free Plasma

Computation of Tokamak Equilibria With Steady Flow

1987 ◽  
Vol 42 (10) ◽  
pp. 1154-1166 ◽  
Author(s):  
W. Kerner ◽  
S. Tokuda
Keyword(s):  
Steady Flow ◽  
Stationary Flow ◽  
Plasma Boundary ◽  
Ideal Mhd ◽  
Mhd Equilibria ◽  
Free Plasma

The equations for ideal MHD equilibria with stationary flow are re-examined and addressed as numerically applied to tokamak configurations with a free plasma boundary. Both the isothermal (purely toroidal flow) and the poloidal flow cases are treated. Experiment-relevant states with steady flow (so far only in the toroidal direction) are computed by the modified SELENE40 code.

Three-dimensional MHD equilibrium in the presence of bootstrap current for the Large Helical Device

1992 ◽  
Vol 32 (9) ◽  
pp. 1499-1513 ◽  
Author(s):  
K Watanabe ◽  
N Nakajima ◽  
M Okamoto ◽  
Y Nakamura ◽  
M Wakatani
Keyword(s):  
Three Dimensional ◽  
Mhd Equilibrium ◽  
Bootstrap Current

scholarly journals A 3-D MHD equilibrium description of nonlinearly saturated ideal external kink/peeling structures in tokamaks

2015 ◽  
Vol 81 (6) ◽  
Author(s):  
W. A. Cooper ◽  
J. P. Graves ◽  
B. P. Duval ◽  
L. Porte ◽  
H. Reimerdes ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Linear Instability ◽  
Equilibrium States ◽  
Driving Mechanism ◽  
Pressure Gradients ◽  
Mhd Equilibrium ◽  
Vacuum Interface ◽  
Mhd Stability ◽  
Bootstrap Current ◽  
External Kink

Novel free boundary magnetohydrodynamic equilibrium states with spontaneous three-dimensional (3-D) deformations of the plasma–vacuum interface are computed. The structures obtained look like saturated ideal external kink/peeling modes. Large edge pressure gradients yield toroidal mode number $n=1$ distortions when the edge bootstrap current is large and higher $n$ corrugations when this current is small. Linear ideal MHD stability analyses confirm the nonlinear saturated ideal kink equilibrium states produced and we can identify the Pfirsch–Schlüter current as the main linear instability driving mechanism when the edge pressure gradient is large. The dominant non-axisymmetric component of this Pfirsch–Schlüter current drives a near resonant helical parallel current density ribbon that aligns with the near vanishing magnetic shear region caused by the edge bootstrap current. This current ribbon is a manifestation of the outer mode previously found on JET (Solano 2010). We claim that the equilibrium corrugations describe structures that are commonly observed in quiescent H-mode tokamak discharges.

scholarly journals Тороидальные альфвеновские моды в плазме токамака Глобус-М

2018 ◽  
Vol 44 (2) ◽  
pp. 65
Author(s):  
В.К. Гусев ◽  
А.А. Мартынов ◽  
С.Ю. Медведев ◽  
Ю.В. Петров ◽  
М.И. Патров ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Boundary Surface ◽  
Stability Margin ◽  
Plasma Boundary ◽  
Magnetic Axis ◽  
Spherical Tokamak ◽  
Equilibrium Configurations ◽  
Alfven Eigenmodes ◽  
Free Plasma ◽  
Lower Frequencies

AbstractConditions of the excitation of toroidal Alfvén eigenmodes (TAEs) and their inf luence on the confinement of fast particles into the Globus-M spherical tokamak have been studied by KINX code calculations of the magnetohydrodynamic spectra of reconstructed divertor equilibrium configurations with stability margin q _0 > 1 on the magnetic axis. The sensitivity of the frequencies of TAE modes with toroidal wavenumber n = 1 to the type of boundary conditions and choice of boundary surface has been studied. It has been established that the frequencies of modes with dominating poloidal harmonics m = 1 and 2 in the gap of continuum are significantly higher than those observed in the spectra of signals measured in the Mirnov coil probes, especially under the assumption of free plasma boundary with allowance for its compressibility. The TAE modes with lower frequencies and higher poloidal wavenumbers localized near the plasma boundary may be responsible for the oscillations observed in the experiment. However, these modes are characterized by the interaction with continuum and, probably, exhibit related damping.

On the Stability of Axisymmetric MHD Modes

1988 ◽  
Vol 43 (12) ◽  
pp. 1009-1016 ◽  
Author(s):  
D. Lortz
Keyword(s):  
Equatorial Plane ◽  
Stability Problem ◽  
Plasma Boundary ◽  
Test Functions ◽  
Shift Condition ◽  
Ideal Mhd ◽  
Mhd Equilibria ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Free Plasma

The stability of axisymmetric ideal MHD equilibria which are symmetric with respect to the equatorial plane is considered. It is found that for external axisymmetric modes which are antisymmetric with respect to the equatorial plane and for profiles such that the current density vanishes at the free plasma boundary the stability problem reduces to a classical interior-exterior scalar eigenvalue problem. Because of the separation property the resulting stability condition is necessary and sufficient and is thus more stringent than criteria derived by choosing special test functions, e.g. the vertical shift condition.

Bootstrap current control in stellarators

1989 ◽  
Vol 1 (8) ◽  
pp. 1663-1670 ◽  
Author(s):  
K. C. Shaing ◽  
B. A. Carreras ◽  
N. Dominguez ◽  
V. E. Lynch ◽  
J. S. Tolliver
Keyword(s):  
Current Control ◽  
Bootstrap Current

Studies on the Thromboplastic Effect of Human Plasma Lipoproteins

1976 ◽  
Vol 35 (01) ◽  
pp. 178-185 ◽  
Author(s):  
Helena Sandberg ◽  
Lars-Olov Andersson
Keyword(s):  
High Density Lipoprotein ◽  
Human Plasma ◽  
Platelet Rich Plasma ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Plasma Lipoproteins ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Free Plasma ◽  
Good Agreement

SummaryHuman plasma lipoprotein fractions were prepared by flotation in the ultracentrifuge. Addition of these fractions to platelet-rich, platelet-poor and platelet-free plasma affected the partial thromboplastin and Stypven clotting times to various degrees. Addition of high density lipoprotein (HDL) to platelet-poor and platelet-free plasma shortened both the partial thromboplastin and the Stypven time, whereas addition of low density lipoprotein and very low density lipoprotein (LDL + VLDL) fractions only shortened the Stypven time. The additions had little or no effect in platelet-rich plasma.Experiments involving the addition of anti-HDL antibodies to plasmas with different platelet contents and measuring of clotting times produced results that were in good agreement with those noted when lipoprotein was added. The relation between structure and the clot-promoting activity of various phospholipid components is discussed.

Stability of Prostacyclin in Human Plasma and Whole Blood: Studies on the Protective Effect of Albumin

1981 ◽  
Vol 46 (03) ◽  
pp. 645-647 ◽  
Author(s):  
M A Orchard ◽  
C Robinson
Keyword(s):  
Platelet Aggregation ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Protective Effect ◽  
Whole Blood ◽  
Bovine Serum ◽  
Fatty Acid Content ◽  
Krebs Solution ◽  
Antiaggregatory Activity ◽  
Free Plasma

SummaryThe biological half-life of prostacyclin in Krebs solution, human cell-free plasma or whole blood was measured by bracket assay on ADP-induced platelet aggregation. At 37°C, pH 7.4, plasma and blood reduced the rate of loss of antiaggregatory activity compared with Krebs solution. The protective effect of plasma was greater than that of whole blood. This effect could be partially mimicked by the addition of human or bovine serum albumin to the Krebs solution. The stabilisation afforded by human serum albumin was dependent on the fatty acid content of the albumin, although this was less important for bovine serum albumin.

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