Free-boundary plasma equilibria with toroidal plasma flows

Abstract Magnetohydrodynamic equilibrium schemes with toroidal plasma flows and the scrape-off layer are developed for the 'divertor-type' and 'limiter-type' free boundaries in the tokamak cylindrical coordinator. With a toroidal plasma flow, the flux functions are considerably different under the isentropic and isothermal assumptions. The effects of the toroidal flow on the magnetic axis shift are investigated. In a high beta plasma, the magnetic shift due to the toroidal flow are almost the same for both the isentropic and isothermal cases, and are about 0.04a0 (a0 is the minor radius) for M0=0.2 (the toroidal Alfvѐn Mach number on the magnetic axis). In addition, the X-point is slightly shifted upward by 0.0125 a0. But the magnetic axis and the X-point shift due to the toroidal flow may be neglected because M0 is usually less than 0.05 in a real tokamak. The effects of the toroidal flow on the plasma parameters are also investigated. The high toroidal flow shifts the plasma outward due to the centrifugal effect. Temperature profiles are noticeable different because the plasma temperature is a flux function in the isothermal case.

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Figures of merit for stellarators near the magnetic axis

Journal of Plasma Physics ◽

10.1017/s0022377820001658 ◽

2021 ◽

Vol 87 (1) ◽

Cited By ~ 1

Author(s):

Matt Landreman

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Axis ◽

Configuration Design ◽

New Paradigm ◽

First Order ◽

Figures Of Merit ◽

Minor Radius ◽

Error Field ◽

Quantities Of Interest

A new paradigm for rapid stellarator configuration design has been recently demonstrated, in which the shapes of quasisymmetric or omnigenous flux surfaces are computed directly using an expansion in small distance from the magnetic axis. To further develop this approach, here we derive several other quantities of interest that can be rapidly computed from this near-axis expansion. First, the $\boldsymbol {\nabla }\boldsymbol {B}$ and $\boldsymbol {\nabla }\boldsymbol {\nabla }\boldsymbol {B}$ tensors are computed, which can be used for direct derivative-based optimization of electromagnetic coil shapes to achieve the desired magnetic configuration. Moreover, if the norm of these tensors is large compared with the field strength for a given magnetic field, the field must have a short length scale, suggesting it may be hard to produce with coils that are suitably far away. Second, we evaluate the minor radius at which the flux surface shapes would become singular, providing a lower bound on the achievable aspect ratio. This bound is also shown to be related to an equilibrium beta limit. Finally, for configurations that are constructed to achieve a desired magnetic field strength to first order in the expansion, we compute the error field that arises due to second-order terms.

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Dynamics of electromagnetic drift-flute waves in high-beta plasmas in the presence of sheared plasma flows

2009 IEEE International Conference on Plasma Science - Abstracts ◽

10.1109/plasma.2009.5227486 ◽

2009 ◽

Author(s):

I. Paraschiv ◽

V. I. Sotnikov ◽

O. G. Onishchenkoa ◽

R. Presura ◽

J. M. Kindel ◽

...

Keyword(s):

Plasma Flows ◽

High Beta

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Influence of Lead on the Interpretation of Bone Samples with Laser-Induced Breakdown Spectroscopy

Journal of Spectroscopy ◽

10.1155/2016/8205479 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6

Author(s):

Abdolhamed Shahedi ◽

Esmaeil Eslami ◽

Mohammad Reza Nourani

Keyword(s):

Plasma Temperature ◽

Laser Induced Breakdown Spectroscopy ◽

Plasma Parameters ◽

Time Duration ◽

Laboratory Rats ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown ◽

Group A ◽

Atomic Lines ◽

Group B

This study is devoted to tracing and identifying the elements available in bone sample using Laser-Induced Breakdown Spectroscopy (LIBS). The bone samples were prepared from the thigh of laboratory rats, which consumed 325.29 g/mol lead acetate having 4 mM concentration in specified time duration. About 76 atomic lines have been analyzed and we found that the dominant elements are Ca I, Ca II, Mg I, Mg II, Fe I, and Fe II. Temperature curve and bar graph were drawn to compare bone elements of group B which consumed lead with normal group, group A, in the same laboratory conditions. Plasma parameters including plasma temperature and electron density were determined by considering Local Thermodynamic Equilibrium (LTE) condition in the plasma. An inverse relationship has been detected between lead absorption and elements like Calcium and Magnesium absorption comparing elemental values for both the groups.

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The temperature characteristics of plasma induced by femtosecond laser radiation

EPJ Web of Conferences ◽

10.1051/epjconf/201922003034 ◽

2019 ◽

Vol 220 ◽

pp. 03034

Author(s):

Sergei Arakelyan ◽

Svetlana Zhirnova ◽

Arkady Galkin ◽

Dmitriy Kochuev ◽

Elena Shamanskaya ◽

...

Keyword(s):

Laser Radiation ◽

Femtosecond Laser ◽

Electron Concentration ◽

Relative Intensity ◽

Collision Frequency ◽

Plasma Temperature ◽

Spectral Lines ◽

Femtosecond Laser Radiation ◽

Plasma Parameters ◽

Atoms And Molecules

In this work, the plasma temperature in an argon and nitrogen medium is measured at various pressure values. Such data can be used to calculate plasma parameters: electron concentration, collision frequency with atoms and molecules, etc. Two approaches are used to measure temperature: using a pyrometer and measuring the relative intensity of spectral lines.

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Toroidal plasma configuration with non-planar magnetic axis

Journal of Plasma Physics ◽

10.1017/s0022377800001975 ◽

1984 ◽

Vol 32 (2) ◽

pp. 179-196

Author(s):

Hussain M. Rizk

Keyword(s):

Cross Section ◽

Ohmic Heating ◽

Circular Cross Section ◽

Magnetic Axis ◽

Toroidal Plasma ◽

Mhd Equilibrium ◽

Special Cases ◽

Magnetic Surfaces ◽

Plasma Configuration ◽

The Ideal

The ideal MHD equilibrium, stability, classical diffusion, effective thermal conductivity, and Ohmic heating of a zero-shear toroidal plasma configuration with a single non-planar magnetic axis of variable torsion and curvature are investigated. The plasma has a circular cross-section through which a longitudinal current density with arbitrary profile flows. In this type of magnetic configuration, the magnetic surfaces arbitrarily rotate around the magnetic axis. This magnetic toroidal configuration is of a stellarator type with a non-planar magnetic axis. The present work also covers as special cases tokamak and a magnetic toroidal plasma configuration with a magnetic axis of arbitrarily modulated curvature.

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Analysis of EUV, Microwave, and Magnetic Field Observations of Solar Plage

International Astronomical Union Colloquium ◽

10.1017/s0252921100029262 ◽

1993 ◽

Vol 141 ◽

pp. 291-294

Author(s):

J W Brosius ◽

J M Davila ◽

H P Jones ◽

W T Thompson ◽

R J Thomas ◽

...

Keyword(s):

Magnetic Field ◽

Longitudinal Magnetic Field ◽

Emission Measure ◽

Plasma Temperature ◽

Microwave Emission ◽

Plasma Parameters ◽

Very Large Array ◽

Hot Plasma ◽

Iron Abundance ◽

Bremsstrahlung Emission

AbstractWe obtained simultaneous images of solar plage on 7 May 1991 with Goddard Space Flight Center’s Solar EUV Rocket Telescope and Spectrograph (SERTS), the Very Large Array (VLA), and the NASA/NSO spectromagnetograph at Kitt Peak. Using intensity ratios of Fe XVI to Fe XV emission lines, we find that the coronal plasma temperature is 2.5 ± 0.3 ×lO6 K throughout the region. The column emission measure ranges from 2.6 × 1027 to 1.3 × 1028 cm−5. The calculated structure and intensity of the 20 cm wavelength thermal bremsstrahlung emission from the hot plasma observed by SERTS is quite similar to the observed structure and intensity of the 20 cm microwave emission observed by the VLA. Using the revised coronal iron abundance of Meyer (1991, 1992), we find no evidence for either cool absorbing plasma or for contributions from thermal gyroemission. Combining the observed microwave polarization and the SERTS plasma parameters, we calculate a map of the coronal longitudinal magnetic field. The resulting values, ~ 30 – 60 Gauss, are comparable to extrapolated values of the potential field at heights of 5,000 and 10,000 km.

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Toroidal equilibrium of rotating plasma with adiabatic constraints

Journal of Plasma Physics ◽

10.1017/s0022377800017815 ◽

1994 ◽

Vol 52 (1) ◽

pp. 129-140 ◽

Cited By ~ 1

Author(s):

A. Gałkowski ◽

R. Żelazny

Keyword(s):

Equilibrium Problem ◽

Stability Criterion ◽

Numerical Technique ◽

Magnetic Axis ◽

Governing Equations ◽

Surface Geometry ◽

Adiabatic Evolution ◽

Flux Surface ◽

Toroidal Plasma

A numerical technique, alternative to Grad's well-known ADM method has been proposed to deal with the slow adiabatic evolution of a toroidal plasma with flow. The equilibrium problem with prescribed adiabatic constraints may be solved by simultaneous calculations of flux surface geometry and original profile functions. Implications for the problem of bifurcation due to nonlinearity of the governing equations are discussed. In the case of field-aligned sub-Alfvénic flow the system is in the second elliptic regime if β <A2/(1 – A2) at the magnetic axis, where A is the Mach Alfvén number of the flow. Super-Alfvénic flows do not satisfy the local firehose stability criterion.

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Electron magnetohydrodynamic turbulence in a high-beta plasma. I. Plasma parameters and instability conditions

Physics of Plasmas ◽

10.1063/1.1314343 ◽

2000 ◽

Vol 7 (11) ◽

pp. 4450-4456 ◽

Cited By ~ 23

Author(s):

R. L. Stenzel ◽

J. M. Urrutia

Keyword(s):

Plasma Parameters ◽

Magnetohydrodynamic Turbulence ◽

High Beta

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Side-conditioned axisymmetric equilibria with incompressible flows

Journal of Plasma Physics ◽

10.1017/s0022377807006769 ◽

2008 ◽

Vol 74 (3) ◽

pp. 327-344 ◽

Cited By ~ 15

Author(s):

G. N. THROUMOULOPOULOS ◽

H. TASSO ◽

G. POULIPOULIS

Keyword(s):

Magnetic Field ◽

Incompressible Flows ◽

Plasma Temperature ◽

Magnetic Axis ◽

Toroidal Shell ◽

Initial Value ◽

Magnetic Field Topology ◽

Equilibrium Configurations ◽

Magnetic Surfaces ◽

The Magnetic Field

AbstractAxisymmetric equilibria with incompressible flows of arbitrary direction are studied in the framework of magnetohydrodynamics under a variety of physically relevant side conditions consisting, for example, in that the plasma temperature or the magnetic field modulus are uniform on magnetic surfaces. To this end a set of pertinent nonlinear ordinary differential equations (ODEs) are transformed to quasilinear ODEs and the respective initial value problem is solved numerically with appropriately determined initial values near the magnetic axis. Several equilibrium configurations are then constructed surface by surface. It turns out that in addition to the usual configurations with a magnetic axis, the non-field aligned flow results to novel toroidal shell equilibria in which the plasma is confined within a couple of magnetic surfaces. In addition, the flow affects the elongation and triangularity of the magnetic surfaces and opens up the possibility of changing the magnetic field topology by creating double toroidal shell-like configurations.

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