POF Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

Search Issue | RSS Feeds RSS
Previous Issue

Dec 1985

Volume 28, Issue 12, pp. 3441-3707

Page 1 of 2 Pages Next Page | Jump to Page

Instability at the interface between two shearing fluids in a channel

Yuriko Renardy

Phys. Fluids 28, 3441 (1985); http://dx.doi.org/10.1063/1.865346 (3 pages) | Cited 51 times

Full Text: | Download PDF

Show Abstract
The linear stability of plane Couette flow composed of two immiscible fluids in layers is considered. The fluids have different viscosities and densities. For the case of equal densities, there is a critical Reynolds number above which the interfacial mode of the bounded problem is approximated by that of the unbounded problem for wavelengths that are not short enough to be in the asymptotic short‐wavelength range, as well as for short waves. The full linear analysis reveals unstable situations missed out by the long‐ and short‐wavelength asymptotic analyses, but which have comparable orders of magnitudes for the growth rates. For the case of unequal densities, it is found that the arrangement with the heavier fluid on top can be linearly stable if the viscosity stratification, volume ratio, surface tension, Reynolds number, and Froude number are favorable.
Show PACS
47.15.Fe Stability of laminar flows
47.20.-k Flow instabilities
68.03.-g Gas-liquid and vacuum-liquid interfaces

Increased particle confinement observed with the use of an external dc bias field in a spheromak experiment

Cris W. Barnes, H. W. Hoida, I. Henins, J. C. Fernández, T. R. Jarboe, and G. J. Marklin

Phys. Fluids 28, 3443 (1985); http://dx.doi.org/10.1063/1.865296 (4 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
Spheromaks are formed in a mesh flux conserver in the presence of an external dc bias magnetic field. The particle confinement is improved when the spheromak separatrix is put inside the metal mesh by the application of positive bias flux. The spheromaks remain stable to tilt instabilities with ratios of bias‐to‐spheromak flux of up to 47±7%.
Show PACS
52.55.Jd Magnetic mirrors, gas dynamic traps

Magnetic surface wave instabilities in plasmas

M. Y. Yu and L. Stenflo

Phys. Fluids 28, 3447 (1985); http://dx.doi.org/10.1063/1.865297 (3 pages) | Cited 55 times

Full Text: | Download PDF

Show Abstract
Techniques of plasma surface wave theory are introduced to obtain new results for magnetic electron waves at the interface of two plasma regions with distinct properties. The procedure generalizes and simplifies problems involving sharp density jumps often encountered in laser– or beam–plasma interaction. As an example, a new magnetic instability is discussed.
Show PACS
52.38.-r Laser-plasma interactions
52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.35.Tc Shock waves and discontinuities

Heat transfer from a cylinder in a time‐dependent cross flow at low Peclet number

B. J. Bayly

Phys. Fluids 28, 3451 (1985); http://dx.doi.org/10.1063/1.865298 (6 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The heat transfer from a constant‐temperature cylinder in a uniform, time‐dependent cross flow at low Peclet number is considered. The time dependence is allowed to be strong, so that the velocity fluctuations may be comparable to, or larger than, the mean flow. The first nontrivial term in the Oseen approximation is calculated using matched‐expansion theory, and its physical significance is discussed. As an illustration, the time‐dependent heat transfer is calculated for a steady cross flow with large sinusoidal perturbations.
Show PACS
47.27.T- Turbulent transport processes
47.10.-g General theory in fluid dynamics
44.90.+c Other topics in heat transfer (restricted to new topics in section 44)

Transport of sedimenting Brownian particles in a rotating Poiseuille flow

A. Nadim, R. G. Cox, and H. Brenner

Phys. Fluids 28, 3457 (1985); http://dx.doi.org/10.1063/1.865299 (10 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Generalized Taylor dispersion theory is used to analyze the convective and diffusive transport of sedimenting colloidal particles occurring within a Poiseuille flow in a horizontal circular pipe that is being rotated slowly about its symmetry axis. Such rigid‐body rotation serves to keep the particles permanently in suspension despite their non‐neutral buoyancy, thereby preventing deposition of the particles on the cylinder bottom. In the ‘‘large’’ particle limit, where transverse diffusion is small compared with sedimentation, expressions are derived for the mean axial velocity and Taylor dispersivity of the colloidal particles. A novel flow field fractionation (FFF) scheme based thereon is proposed for continuously separating particles of different sizes and/or densities.
Show PACS
47.32.Ef Rotating and swirling flows
47.60.-i Flow phenomena in quasi-one-dimensional systems
82.70.Kj Emulsions and suspensions
47.15.-x Laminar flows

High Marangoni number convection in a square cavity

A. Zebib, G. M. Homsy, and E. Meiburg

Phys. Fluids 28, 3467 (1985); http://dx.doi.org/10.1063/1.865300 (10 pages) | Cited 104 times

Full Text: | Download PDF

Show Abstract
The steady thermocapillary motion in a square cavity with a top free surface in the absence of gravitational forces is considered. The cavity is heated from the side with the vertical boundaries isothermal while the horizontal boundaries are adiabatic. The relative change in the surface tension is very small, i.e., an appropriate capillary number tends to zero, so that the free surface is assumed to remain flat at leading order. A finite‐difference method is employed to compute the flow field. Numerically accurate solutions are obtained for a range of Prandtl numbers and for Reynolds numbers Re as high as 5×104. Surface deflections are computed as a domain perturbation for small capillary number. In addition, asymptotic methods are used to infer the boundary layer structure in the cavity, in the limit of large values of the Reynolds and Marangoni numbers. For a fixed Prandtl number Pr, it is shown that the Nusselt number, liquid circulation, and maximum vorticity are asymptotic to Re1/3, Re−1/3, and Re2/3, respectively. These results are in agreement with the computed solutions. The leading‐order solution for the free‐surface deformation is sensitive to the value of Pr. With Pr>1, the depression near the hot corner may exceed the elevation near the cold corner, while a secondary elevation may be induced near the hot corner when Pr<1.
Show PACS
44.30.+v Heat flow in porous media
47.15.Cb Laminar boundary layers

The departure from Darcy flow in natural convection in a vertical porous layer

Dimos Poulikakos and Adrian Bejan

Phys. Fluids 28, 3477 (1985); http://dx.doi.org/10.1063/1.865301 (8 pages) | Cited 28 times

Full Text: | Download PDF

Show Abstract
An analytical and numerical study is reported of steady‐state natural convection in a two‐dimensional porous layer heated from the side. Contrary to previous investigations of the phenomenon, which were all based on the Darcy flow model, a vector generalization of Forchheimer’s one‐dimensional model is used in the present study, which is valid for all values of local Reynolds number based on pore size. A matched boundary layer solution of the type developed by Weber for Darcy flow is developed for the limit of large‐pore Reynolds numbers (the ‘‘non‐Darcy’’ limit). It is shown that the natural convection phenomenon in the non‐Darcy limit is governed by a new dimensionless group, the Rayleigh number for the higher Reynolds number limit, Ra∞. Numerical experiments are reported in the range 1.6×105≤Ra∞≤1.6×109, in a porous layer with height/thickness ratio equal to 2, and with a high value of Darcy modified Rayleigh number (Ra=4000). The numerical experiments confirm the flow features and scales anticipated by the matched boundary layer solution for the non‐Darcy limit. The experiments also document the transition from the well‐known Darcy flow to the large‐pore Reynolds‐number limit treated in this paper.
Show PACS
44.25.+f Natural convection
47.56.+r Flows through porous media

Kinetic theory for plane flows of a dense gas of identical, rough, inelastic, circular disks

J. T. Jenkins and M. W. Richman

Phys. Fluids 28, 3485 (1985); http://dx.doi.org/10.1063/1.865302 (10 pages) | Cited 237 times

Full Text: | Download PDF

Show Abstract
Grad’s method of moments is employed to derive balance laws and constitutive relations for plane flows of a dense gas consisting of identical, rough, inelastic, circular disks. Two temperatures are involved; these are proportional to the kinetic energies associated with fluctuations in translational velocity and spin, respectively. When the single particle velocity distribution function is assumed to be close to a two‐temperature Maxwellian, two distinct theories are obtained. One applies when the particles are almost smooth and the collisions between them are nearly elastic; the other applies to nearly elastic particles that, in a collision, almost reverse the relative velocity of their points of contact. I both cases energy is nearly conserved in collisions.
Show PACS
51.10.+y Kinetic and transport theory of gases
05.20.Dd Kinetic theory
05.60.-k Transport processes

The thick, turbulent boundary layer on a cylinder: Mean and fluctuating velocities

Richard M. Lueptow, Patrick Leehey, and Thomas Stellinger

Phys. Fluids 28, 3495 (1985); http://dx.doi.org/10.1063/1.865417 (11 pages) | Cited 24 times

Full Text: | Download PDF

Show Abstract
The mean and fluctuating velocities in a turbulent boundary layer on a cylinder have been experimentally characterized for the case where the boundary layer is thick compared to the radius of transverse curvature. The mean velocity measurements suggest a mixed scaling for the ‘‘log law of the wall’’ using the wall coordinate yUτ/ν and the ratio of the local boundary layer thickness to the radius of the cylinder δ/a. A relation for the slope and intercept of the log law of the wall as functions of δ/a based on empirical results and simple analysis is presented. Measurements of the Reynolds stress for δ/a of order 10 show that the Reynolds stress drops off much more quickly with distance from the wall than for a turbulent boundary layer on a flat plate. Both the Reynolds stress data and the turbulent intensity in the mean flow direction data are functions of the inverse radial distance from the center of the cylinder.
Show PACS
47.27.nb Boundary layer turbulence

Laminar‐turbulent transition in a slowly pulsating pipe flow

Lev Shemer

Phys. Fluids 28, 3506 (1985); http://dx.doi.org/10.1063/1.865303 (4 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Transitional pulsating flow in a pipe is investigated experimentally in the frequency region where its behavior is assumed to be quasisteady. Instantaneous velocity measurements were performed at several radial locations at the exit plane of the pipe. The output of flush‐mounted hot wires at two upstream positions was also recorded simultaneously. The results indicate that the quasisteady assumption is valid in general. The flow behavior is the function primarily of the instantaneous Reynolds number, although the laminarization process and retransition to turbulence are qualitatively different. The laminarization at subcritical instantaneous Reynolds numbers in a time‐dependent flow is a gradual process, similar to the observed turbulence decay in flow geometries where Re is varied spatially. The retransition to turbulence occurs by means of the generation of turbulent slugs at various locations along the pipe. These slugs are convected downstream and coalesce, eventually resulting in fully developed turbulent flow in the whole pipe at higher instantaneous Reynolds numbers.
Show PACS
47.60.-i Flow phenomena in quasi-one-dimensional systems
47.20.-k Flow instabilities
47.27.nb Boundary layer turbulence
47.90.+a Other topics in fluid dynamics (restricted to new topics in section 47)

The possibility of a resonance mechanism in the developing two‐dimensional jet

F. O. Thomas and V. W. Goldschmidt

Phys. Fluids 28, 3510 (1985); http://dx.doi.org/10.1063/1.865304 (5 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
An experimental investigation of a developing planar turbulent jet discharging into a quiescent environment was undertaken. The measurements now reported suggest that the pressure field associated with the large‐scale flow structures occurring downstream excite the nascent jet shear layers near the jet exit. Such structures are characterized by the formation of an antisymmetric structural array near the end of the potential core and extending far into the similarity region. The results suggest that coupling or feedback between downstream coherent structures and the initial region may be important in the development of the flow.
Show PACS
47.27.wg Turbulent jets
47.90.+a Other topics in fluid dynamics (restricted to new topics in section 47)

Flow field effects on nucleation in a reacting mixing layer

I. M. Kennedy

Phys. Fluids 28, 3515 (1985); http://dx.doi.org/10.1063/1.865305 (10 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Chemical nucleation has been studied numerically in a stagnation point mixing layer in which reactants in two counter‐flowing streams form a condensable monomer. The response of the subsequent nucleation kinetics to the velocity gradient in the flow is described in terms of a Damkohler number. Two limiting cases have been established. First, if the Damkohler number for monomer production is small, i.e., the rate of monomer production is slow, then the nucleation of particles can be strongly affected by the flow field in a manner which is equivalent to the effect of supersaturation in a uniform vapor. Second, if the Damkohler numbers for cluster growth are small (because of a small accommodation factor for monomer–cluster interactions), the concentrations of clusters do not achieve equilibrium levels. This can result in the suppression of particle formation over a critical range of Damkohler numbers. In this case the behavior of the nucleation kinetics is analogous to the transient phase of nucleation in a uniform vapor.
Show PACS
82.60.Nh Thermodynamics of nucleation
47.70.Fw Chemically reactive flows
82.33.Vx Reactions in flames, combustion, and explosions
82.70.Rr Aerosols and foams

The evolution of axisymmetric vortex systems in liquid He II

W. Fiszdon, Z. Peradzynski, and W. Poppe

Phys. Fluids 28, 3525 (1985); http://dx.doi.org/10.1063/1.865306 (9 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The main features of the evolution of the normal and superfluid vorticity distributions (for high line density) in liquid helium are investigated for simple systems in the case of axial symmetry. The variation of initially Gaussian and top‐hat vorticity distributions for different ratios of the two components is analyzed. The ratio of the obtained characteristic time scales of the variation of the vorticity on the centerline and the spreading of the vorticity distribution depends essentially on the initial conditions.
Show PACS
67.25.dk Vortices and turbulence
47.32.Ef Rotating and swirling flows

Nonlinear waves in superposed magnetic fluids

Rama Kant and S. K. Malik

Phys. Fluids 28, 3534 (1985); http://dx.doi.org/10.1063/1.865307 (4 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
An asymptotic weakly nonlinear wave propagation in Rayleigh–Taylor magnetic fluid flows is investigated. The waves are found to be unstable against modulation. The stability analysis reveals that there exist two regions of instabilities. The magnetic field has a stabilizing influence in one region and an opposite effect in the second region. The nonlinear cutoff wavenumber which separates the region of stability from that of instability is also obtained. The magnetic field has a destabilizing effect on the cutoff wavenumber.
Show PACS
75.50.Mm Magnetic liquids
47.55.Kf Particle-laden flows
47.90.+a Other topics in fluid dynamics (restricted to new topics in section 47)

Plasma kinetic theory in action‐angle variables

S. M. Mahajan and C. Y. Chen

Phys. Fluids 28, 3538 (1985); http://dx.doi.org/10.1063/1.865308 (8 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
An appropriate canonical perturbation theory to correctly deal with general electromagnetic field perturbation is developed and is used to set up plasma kinetic theory in action‐angle variables. A variety of test problems are solved to show the unifying power of the method. Basic linear, quaislinear, and nonlinear equations, which can serve as the starting point for a whole range of plasma problems, are derived.
Show PACS
52.25.Dg Plasma kinetic equations
05.20.Dd Kinetic theory

The dispersion functional for multidimensional equilibria

H. Ralph Lewis, Daniel C. Barnes, James L. Schwarzmeier, and Charles E. Seyler

Phys. Fluids 28, 3546 (1985); http://dx.doi.org/10.1063/1.865309 (11 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
Numerical study of the linear stability of plasmas is very difficult when one or more of the plasma species is collisionless and the equilibrium is multidimensional, that is, characterized by two or more nonignorable spatial coordinates. The problem arises, for example, in evaluating kinetic stabilizing effects on the internal tilting mode (an n=1 ballooning mode) in field‐reversed configurations. In this paper, the Laplace transform of the perturbation distribution function for a collisionless species is derived for all classes of phase‐space trajectories and used to construct the dispersion functional for multidimensional equilibria. The kinetic part of the dispersion functional is expressed in terms of the Laplace transform of autocorrelation functions with respect to a certain delay time. It is shown how to obtain the same result formally by using Liouville eigenfunctions. For the case of the Vlasov‐fluid model, the dispersion functional is transformed in a way that is particularly appropriate for computation of the kinetic stability of field‐reversed configurations to the internal tilting mode.
Show PACS
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.55.Jd Magnetic mirrors, gas dynamic traps
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)

The long‐time evolution approximation for a quasi‐one‐dimensional plasma system

E. J. Caramana

Phys. Fluids 28, 3557 (1985); http://dx.doi.org/10.1063/1.865310 (10 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
The long‐time evolution of a plasma through a series of equilibrium states for the case of the field‐reversed configuration (FRC) is considered. A formulation of the transport model in magnetic flux variables is given for the approximate geometry where the magnetic field lines are straight. Thus a complicated two‐dimensional elliptic differential equation amenable only to numerical solution is avoided. Radial force balance is enforced pointwise while axial force balance is enforced only globally. The equations formulated in this manner are relatively simple; some of their salient features are discussed. Although a particular plasma–magnetic field configuration is considered, the type of analytical method presented is more general and applies to other coupled initial‐boundary value problems. The absence of complicated geometry and flux surface averaging involved for other systems makes the essential aspects of the transformations employed transparent.
Show PACS
52.55.Dy General theory and basic studies of plasma lifetime, particle and heat loss, energy balance, field structure, etc.

Physical mechanisms for hot‐electron stabilization of low‐frequency interchange modes

Heiji Sanuki and Francis F. Chen

Phys. Fluids 28, 3567 (1985); http://dx.doi.org/10.1063/1.865311 (5 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The stabilization of low‐frequency background and hot‐electron interchange modes is studied by using a relatively simple multi‐fluid model. Physical pictures for the stabilization mechanisms such as the ‘‘charge‐uncovering’’ effect are given and compared with the stabilization of interchange modes by the finite Larmor radius (FLR) effect.
Show PACS
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.55.Jd Magnetic mirrors, gas dynamic traps

Nearly perpendicular wave propagation at the fundamental electron‐cyclotron resonance

Kaya Imre and Harold Weitzner

Phys. Fluids 28, 3572 (1985); http://dx.doi.org/10.1063/1.865312 (9 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Waves propagating nearly perpendicular to the equilibrium magnetic field across the fundamental cyclotron resonance layer are studied by a boundary layer analysis for a weakly relativistic, inhomogeneous Vlasov plasma. The plasma is assumed to be perpendicularly stratified. It is found that the wave energy associated with the ordinary mode transmitted through the layer is independent of the relativistic corrections and is given by a geometrical optics formula. It is also found that there is no reflected energy associated with this mode when it is incident from the high‐field side. These results are the same as the nonrelativistic case with purely perpendicular propagation. Relativistic effects produce a significant reduction of the reflection coefficient for low‐field side incidence from the nonrelativistic value. Correspondingly, for this mode there is a considerable increase in the absorption rate for sufficiently high, but moderate, electron density and temperature.
Show PACS
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.27.Ny Relativistic plasmas
52.50.Gj Plasma heating by particle beams

Linear and nonlinear evolution of double‐humped ion distributions in strong unmagnetized shock structures

Kanji Abe and Gyo Sakaguchi

Phys. Fluids 28, 3581 (1985); http://dx.doi.org/10.1063/1.865313 (9 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Ion distributions in shock structures are determined from the Fokker–Planck equation. If the shock Mack number is high, and the electron temperature Te in the shock structure is sufficiently higher than the ion temperature T1 far ahead of the shock wave, the ion distribution has a double‐humped shape, and is unstable in the sense of a linear Landau analysis. Characteristic times in which the wave–ion interaction, the wave–wave interaction, and the ion trapping modify the ion distribution and/or the Landau‐amplified electric field to a certain extent are estimated. If Te/T1 and the shock Mach number are sufficiently high, the wave–ion interaction has a strong influence on the evolution of the ion distribution, and competes with the ion–ion collisions in the shock structure.
Show PACS
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.25.Fi Transport properties
52.35.Tc Shock waves and discontinuities
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)

Effects of particle trapping on ion‐cyclotron resonance heating in a toroidal plasma

D. Anderson, M. Lisak, and L.‐O. Pekkari

Phys. Fluids 28, 3590 (1985); http://dx.doi.org/10.1063/1.865314 (4 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
The effect of particle trapping on the velocity space diffusion caused by ion‐cyclotron resonance heating is considered. A bounce‐averaged Fokker–Planck equation is derived, which determines the distribution function of the heated ions. Trapped particle effects lead to significant changes in the rf‐driven diffusion operator as compared to previously used models.
Show PACS
52.50.Gj Plasma heating by particle beams
52.20.Dq Particle orbits
52.25.Dg Plasma kinetic equations

Toroidally linked mirrors

H. R. Strauss, L. Friedland, and M. Kishinevsky

Phys. Fluids 28, 3594 (1985); http://dx.doi.org/10.1063/1.865315 (4 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Mirrors linked by toroidal segments may be stabilized by ponderomotive force produced by electromagnetic waves at the ion‐cyclotron frequency. This may provide a simple alternative to tandem mirrors and bumpy tori. Approximate calculations of equilibrium, stability, and diffusion are given.
Show PACS
52.20.Dq Particle orbits
28.52.Av Theory, design, and computerized simulation
52.55.-s Magnetic confinement and equilibrium
52.55.Jd Magnetic mirrors, gas dynamic traps
52.50.Gj Plasma heating by particle beams

Radial diffusion of energetic tail ions driven by electromagnetic waves of ion‐cyclotron range of frequencies in bumpy torus and tokamak geometry

C. S. Chang

Phys. Fluids 28, 3598 (1985); http://dx.doi.org/10.1063/1.865316 (11 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
Radial particle and energy transport of the high‐energy tail ions created by fundamental resonance heating of ion‐cyclotron range of frequency waves is studied for tokamak and bumpy torus geometry. The lowest‐order distribution function for the high‐energy ions is calculated in a two‐dimensional velocity space, and all the diffusion coefficients are explicitly evaluated.
Show PACS
52.50.Gj Plasma heating by particle beams
52.25.Fi Transport properties
52.55.Jd Magnetic mirrors, gas dynamic traps
52.55.Fa Tokamaks, spherical tokamaks

Nonambipolar radial particle transport in a tandem mirror

E. B. Hooper, R. H. Cohen, D. L. Correll, J. M. Gilmore, and D. P. Grubb

Phys. Fluids 28, 3609 (1985); http://dx.doi.org/10.1063/1.865317 (10 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
Nonambipolar transport has been measured in the tandem mirror TMX‐U [Phys. Rev. Lett. 53, 783 (1984)] by applying charge conservation to the measured electron currents to the end walls. The resulting confinement time τ⊥ is found to depend upon the central‐cell potential ϕ approximately as τ⊥(msec) =3ϕ(kV)−2. The transport rate, deduced from the data, agrees to within a factor of 1–5 with resonant‐transport theory applied to the measured plasma parameters. Attempts to include radial effects by modeling the plasma self‐consistently using resonant transport are less successful; near the axis the transport coefficients become too small to explain the equilibrium. Modeling using an ad hoc ϕ−2 law for the transport coefficients is more successful.
Show PACS
28.52.Av Theory, design, and computerized simulation
52.55.-s Magnetic confinement and equilibrium
52.55.Pi Fusion products effects (e.g., alpha-particles, etc.), fast particle effects
52.25.Fi Transport properties

A one‐dimensional model for lower‐hybrid current drive including perpendicular dynamics

V. Fuchs, R. A. Cairns, M. M. Shoucri, K. Hizanidis, and A. Bers

Phys. Fluids 28, 3619 (1985); http://dx.doi.org/10.1063/1.865318 (10 pages) | Cited 47 times

Full Text: | Download PDF

Show Abstract
The two‐dimensional (velocity space) Fokker–Planck equation for lower‐hybrid current drive is approximated by its perpendicular moments hierarchy closed in the second moment equation. The closure is derived on the basis of a distribution function composed of a central thermal Maxwellian plus a perpendicularly broadened distribution of fast particles that are diffused into, and pitch‐angle scattered out of, the quasilinear plateau region. The resulting one‐dimensional model reproduces the relevant features of the solutions obtained from numerically integrating the two‐dimensional Fokker–Planck equation. An analytic estimate of the perpendicular temperature on the plateau and the plateau height as a function of spectrum width and position is presented. Also predicted are the current density generated and its figure of merit (the current density per unit power density dissipated).
Show PACS
52.25.Fi Transport properties
52.50.Gj Plasma heating by particle beams
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close