2 edition of **High n ballooning modes in highly elongated tokamaks** found in the catalog.

High n ballooning modes in highly elongated tokamaks

C. H An

- 325 Want to read
- 17 Currently reading

Published
**1980**
by Dept. of Energy, Oak Ridge National Laboratory, for sale by the National Technical Information Service] in Oak Ridge, Tenn, [Springfield, Va
.

Written in

- Tokamaks,
- Plasma stability

**Edition Notes**

Statement | C. H. An, University of Tennesse, Knoxville and GLenn Batemen, School of Nuclear Engineering, Georgia Institute of Technology ; prepared by the Oak Ridge National Laboratory |

Series | ORNL/TM ; 7074 |

Contributions | Bateman, Glenn, joint author, University of Tennessee, Knoxville, Georgia Institute of Technology. School of Nuclear Engineering, Oak Ridge National Laboratory |

The Physical Object | |
---|---|

Pagination | v, 45 p. : |

Number of Pages | 45 |

ID Numbers | |

Open Library | OL14881972M |

limited by high n ballooning mode instabilities, wher e both the first and second stability limits are considered. The effect of the bootstrap current, which reduces the magnetic shear in the steep pressure gradient region at the edge of the H-mode plasma, can result in access to the second stability of ballooning mode. N region, while in DIII-D, both q 95 and s 95 showed increase by up to % with the SF con guration. Plasma shaping Highly shaped plasmas tend to be more stable in both NSTX and DIII-D with access to smaller-size ELM regimes, higher pedestal pressures and the associ-ated stabilization of certain mode types, e.g., ideal ballooning modes.

H-Mode plasmas, based on Thomson-scattering measurements, a clear correlation of the density limit of the tokamak H-Mode high-con nement regime with the approach to the ideal ballooning instability threshold at the periphery of the plasma. Based on the prediction of the tokamak scrape-o layer width by an empirical scaling [3], over a wide. In this and the accompanying paper, the problem of the maximally achievable elongation ${\it\kappa}$ in a tokamak is investigated. The work represents an extension of many earlier studies, which were often focused on determining ${\it\kappa}$ limits due to (i) natural elongation in a simple applied pure vertical field or (ii) axisymmetric stability in the presence of a perfectly .

The method has been validated by comparing results about nonlinear saturation of ballooning modes in tokamaks with numerical data from the PEST code. Full text Get a printable copy (PDF file) of the complete article (K), or click on a page image below to browse page by page. high-n ballooning modes requires the local quantities as well as ﬂux surface quantities. Within the framework of the three-dimensional ~3D! ballooning formalism,1 it was found that in 3D systems such as heliotrons, the above classiﬁcation on the structure of the pressure-driven modes in tokamaks is.

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Get this from a library. High n ballooning modes in highly elongated tokamaks. [C H An; Glenn Bateman; University of Tennessee, Knoxville.; Georgia Institute of Technology.

School of Nuclear Engineering.; Oak Ridge National Laboratory.]. The variational principle derived by Choe and Freidberg [Phys. Flu ()] and used to estimate the geometry of high‐beta tokamak equilibria is extended to include elongation.

Ballooning mode stability is then investigated, illustrating the influence of Cited by: 6. The effect of energetic trapped particles on the stabilization of high toroidal mode number (n → ∞) ballooning modes in tokamaks is investigated numerically in the low frequency limit, for a.

stability analysis of the ballooning mode [3,4] has been a crucial issue in tokamak fusion research. Plasmas in the pedestal region of tokamaks often rotate. The plasma rotation affects linear stability of MHD ballooning modes.

It was numerically found that toroidal rotation shear stabilizes ideal MHD high-n ballooning modes (n: toroidal mode. Fixed boundary ideal magnetohydrodynamic (MHD) instabilities were studied analytically and computationally for highly elongated axisymmetric toroidal equilibria.

The analytic results for high n ballooning modes were compared with computational results obtained by using ORNL BALOON code.

The computational results reveal that high elongation, low aspect ratio, and Author: C. High-n ballooning modes in highly elongated tokamaks. An analytic study of stability against high-n ballooning modes in highly elongated axi-symmetric plasmas is presented and compared with computational results.

– From the equation for the marginal pressure gradient, it is found that local shear has an important effect on the stability. Another ballooning mode, the collisionless analogue of the Carreras–Diamond mode [Carreras, Diamond, Murakami, Dunlap et al., Phys.

Rev. Lett. 50, ()] can also be. ANNALS OF PHYSICS() High-n Ideal and Resistive Shear Alfvén Waves in Tokamaks C. CHENG, LIU CHEN, AND M. CHANCE Plasma Physics Laboratory, Princeton University, P.O.

BoxPrinceton, New Jersey Received May 1, Ideal and resistive MHD equations for the shear Alfvén waves are studied in a low-Í1 toroidal model by employing the high-n ballooning.

In highly elongated tokamaks, for example, hand, the codes described in refs. [3,4,6,11] assume the shape of the plasma boundary must be accu- fixed coil currents. This implies that a trial-and-er rately controlled, in order to maintain axisymmet- ror method must be used if one wants to compute ric stability throughout the discharge.

However, in accordance with, the n = 1 external kink limit is β N =while the n > 1 mode limits coincide with the high-n ballooning limit: β N N = for the n = 1 mode, which is likely due to coupling to both the m = 1 mode for.

The nonlinear dynamics of magneto-hydrodynamic ballooning mode perturbations is conjectured to be characterised by the motion of isolated elliptical flux tubes.

The theory of stability, dynamics and saturation of such tubes in tokamaks is developed using a generalised Archimedes’ principle.

The equation of motion for a tube moving against a drag force in a general axisymmetric. HIGH ORDERING FOR KBMS EQUATION The basic theory of kinetic ballooning modes was developed in Ref.

[16]. Here, the authors solve the gyrokinetic equation by expanding in "= v 2 thi =!l 2 c ˝1, where v thi= p 2T i=m i is the ion thermal speed, l cthe connection length and!˝v the=l cis the mode frequency, with v the the electron thermal. The linear stability of high-toroidal-number drift-ballooning modes in tokamaks is investigated with a model that includes resistive and viscous dissipation, and assumes the mode frequency to be comparable to both the sound and diamagnetic frequencies.

The coupled effect of ion drift waves and electron drift-acoustic waves is shown to be important, resulting in. T1 - THE MODE STRUCTURE OF HIGH-N RESISTIVE BALLOONING MODES. AU - CONNOR, J W. AU - HASTIE, R J. AU - WILSON, H R. PY - /1. Y1 - /1. N2 - The higher-order corrections (in an n-1/2 expansion) to resistive ballooning theory are analyzed in order to gain information about the radial structure of the DELTA'-driven modes.

The stability to high-n modes is analyzed with a localized ballooning code, BLOON. The attainment of. is facilitated by an automated optimization search on shape and current parameters.

The equilibria are calculated with a free-boundary equilibrium code using coils appropriate for the Doublet III experimental device. Ballooning transform is essential method to analyze 2D mode structure in toroidal geometry not only to ideal Ballooning mode, but also for high n toroidal drift waves and Alfven eigenmodes.

Fundamentals of ballooning mode structure in toroidal plasma is discussed for the application to MHD instabilities and toroidal drift waves.

@article{osti_, title = {Higher order collisionless ballooning mode in tokamaks}, author = {Hirose, A and Zhang, L and Elia, M}, abstractNote = {Kinetic stability analysis of general electromagnetic modes in tokamaks has revealed the existence of higher order ballooning mode which is not subject to second stabilization.

The kinetic ballooning mode in the. Role of explosive instabilities in high- disruptions in tokamaks 5 Figure 2. (a) Perturbed pressure contours for the n= 1 mode using the safety factor pro le q I in Fig. 1 (a). Note the ballooning nature of the eigenfunction.

(b) Poloidal spectrum of the kinetic energy for the n= 1 mode. ballooning modes which involve a critical pressure gradient length [3]. These codes yield a consistent description of transport processes from the small scale uctuations to the equilibrium pro les.

Several issues are addressed here: the 3-D structure of the radially elongated large scale transport event (streamer) and its non linear character. Mechanism of Stabilization of Ballooning Modes by Toroidal Rotation Shear in Tokamaks M.

Furukawa* and S. Tokuda Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Naka, IbarakiJapan. A ballooning perturbation in a toroidally rotating tokamak is expanded by square-integrable eigenfunctions of an eigenvalue problem associated with ballooning modes in a static plasma.

Especially a weight function is chosen such that the eigenvalue problem has only the .Aiba N. et al., The Effect of the Aspect Ratio on the External Kink-Ballooning Instability in High-β Tokamaks 3 BB R ttR c c =×, 0 0 (3) II R ppR c c 0 ×, 0 (4) where R c is the major radius and the subscript 0 means the values when the aspect ratio A =as B t0 = and R c0 = “An Extension of the Theory for Neutral Beam Driven Currents in Tokamaks”, Fusion Techn., 19, (); W.

M. Stacey and J. Mandrekas. “Saturated tearning modes in toroidal geometry”, Phys. Flu (). G. Bateman and R. N. Norris. “High-n ballooning modes in highly elongated plasmas”, Nucl.

Fus 55 (