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Dec 1980

Volume 23, Issue 12, pp. 2339-2563

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Equilibrium shapes of a pair of equal uniform vortices

P. G. Saffman and R. Szeto

Phys. Fluids 23, 2339 (1980); http://dx.doi.org/10.1063/1.862935 (4 pages) | Cited 60 times

Online Publication Date: 21 July 2008

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The shapes and properties of two equal corotating uniform vortices, rotating steadily about each other, are calculated. An integrodifferential equation for the bounding contour is solved numerically, using Newton’s method. The results compare well with those obtained from a simple model. It is shown that steady solutions do not exist if the vortices are too close. The stability to two‐dimensional disturbances is discussed qualitatively and the critical separation at which the system becomes unstable is calculated. Some comments are made on the stability of a vortex pair of equal counter rotating uniform vortices.
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47.10.-g General theory in fluid dynamics
47.32.Ef Rotating and swirling flows

Mixing of passive scalar stripes by a three‐dimensional multi‐mode vector field

J. L. Fournier, J. N. Gence, and G. Comte‐Bellot

Phys. Fluids 23, 2343 (1980); http://dx.doi.org/10.1063/1.862936 (5 pages)

Online Publication Date: 21 July 2008

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An attempt is made to generalize the work of Corrsin and Karweit by considering the pure convection of a passive scalar by a three‐dimensional multi‐mode and time‐independent random isotropic vector field made up of different Fourier modes. It can be roughly concluded that an initially nonisotropic scalar field has a tendency to return to isotropy under the influence of the mixing. However, it appears that the ratio of the Taylor scales corresponding to two perpendicular directions tends to a value less than one when t is growing. This result is independent of the number of modes.
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47.27.T- Turbulent transport processes
47.27.Gs Isotropic turbulence; homogeneous turbulence

The unsteady flux of heat and momentum from a flat plate

Rolf G. Lueck

Phys. Fluids 23, 2348 (1980); http://dx.doi.org/10.1063/1.862937 (8 pages) | Cited 2 times

Online Publication Date: 21 July 2008

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The unsteady viscous fluid stress on a flat plate was computed numerically from a simplified unsteady momentum equation which is not restricted by a frequency parameter and compares favorably with the available (frequency restricted) calculations. The unsteady heat flux from the same plate is examined for three boundary conditions: (a) free‐stream speed oscillations with a constant surface and free‐stream temperature, (b) free‐stream temperature oscillations with a constant surface temperature and constant free‐stream speed, and (c) uniform surface temperature oscillations with a constant free‐stream speed and temperature. The heat flux in response to speed oscillations has a maximum value at low frequencies and a larger bandwidth than the response to free‐stream temperature oscillations. When the boundary layer is unsteady, the response of the heat flux to surface temperature oscillations is not comparable to either the response to speed oscillations or the response to free‐stream temperature oscillations. The results have implications for the interpretation and calibration of constant temperature anemometer and constant temperature thermometer output signals in regions with small amplitude temperature and streamwise velocity fluctuations.
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44.25.+f Natural convection

Boundary conditions for thin lubrication layers

Daniel D. Joseph

Phys. Fluids 23, 2356 (1980); http://dx.doi.org/10.1063/1.862938 (3 pages) | Cited 10 times

Online Publication Date: 21 July 2008

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In certain circumstances, the effects of a thin lubrication layer may be accommodated by a slip flow boundary condition with the gradient of the tangential component of the velocity at the wall proportional to the square of the tangential component there.
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68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
47.90.+a Other topics in fluid dynamics (restricted to new topics in section 47)

Modulation solitons in inhomogeneous media

L. H. Larsen

Phys. Fluids 23, 2359 (1980); http://dx.doi.org/10.1063/1.862939 (3 pages) | Cited 2 times

Online Publication Date: 21 July 2008

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The propagation of a modulation soliton in a medium with inhomogenities is considered. It is shown that the center of the wave packet obeys a Newtonian force equation with the inhomogenity acting as the force. The model equation is compared with numerical solutions of the inhomogeneous nonlinear Schrödinger equation.
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41.20.Jb Electromagnetic wave propagation; radiowave propagation

Phenomenological model of shock initiation in heterogeneous explosives

E. L. Lee and C. M. Tarver

Phys. Fluids 23, 2362 (1980); http://dx.doi.org/10.1063/1.862940 (11 pages) | Cited 74 times

Online Publication Date: 21 July 2008

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An ignition and growth concept is used, within the framework of a one‐dimensional Lagrangian hydrodynamic code, to model the shock initiation of heterogeneous solid explosives. The leading shock wave of an initiating pulse is assumed to ignite a small fraction of the explosive at localized heated regions. These ignited regions then grow as material is consumed at their boundaries. The growth rate for a particular material is assumed to have the characteristic pressure dependence of high‐pressure laminar burning experiments. Results of the model calculations are in good quantitative agreement with recent manganin pressure gage and particle velocity gage measurements of the buildup of the initiating shock front to detonation for both sustained and short duration pulses in four solid explosives: PBX−9404, TATB, cast TNT, and PETN. The predicted run distances to detonation as functions of shock pressure at various initial densities and the predicted reaction zone lengths of the fully developed detonation waves also correlate well with experimental data for these four solid explosives.
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82.33.Vx Reactions in flames, combustion, and explosions
47.40.Nm Shock wave interactions and shock effects
82.40.Fp Shock wave initiated reactions, high-pressure chemistry

Particle acceleration by an intense solitary electromagnetic pulse

H. M. Lai

Phys. Fluids 23, 2373 (1980); http://dx.doi.org/10.1063/1.862941 (3 pages) | Cited 11 times

Online Publication Date: 21 July 2008

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A stationary charge, while left stationary after the passage of an intense electromagnetic pulse containing many waves, can be efficiently accelerated by a solitary pulse. Its relevance to the acceleration of particles in a magnetically insulated vacuum power transmission line is discussed.
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41.60.-m Radiation by moving charges
84.40.Az Waveguides, transmission lines, striplines

Electron beam dynamics in combined guide and pump magnetic fields for free electron laser applications

L. Friedland

Phys. Fluids 23, 2376 (1980); http://dx.doi.org/10.1063/1.862942 (7 pages) | Cited 82 times

Online Publication Date: 21 July 2008

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The propagation of a cold relativistic electron beam in a free electron laser with an axial guide magnetic field is considered. The possibility of several steady‐state helical trajectories for the electrons is shown, and the stability against perturbations and accessibility of such steady states is considered. Necessary and sufficient conditions for the stability are derived and indicate the importance of the transition region at the entrance of the laser. Possible modes of operation of the laser in different steady‐state regimes are suggested and illustrated by numerical examples.
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41.75.Fr Electron and positron beams
41.60.-m Radiation by moving charges
42.60.By Design of specific laser systems

Steady‐state treatment of relativistic electron beam erosion

William M. Sharp and M. Lampe

Phys. Fluids 23, 2383 (1980); http://dx.doi.org/10.1063/1.862943 (13 pages) | Cited 19 times

Online Publication Date: 21 July 2008

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The head of a relativistic electron beam propagating into un‐ionized or weakly ionized gas is not self‐pinched and expands freely, causing the beam to take on a ’’trumpet’’ shape. The region where the beam pinches, referred to as the ’’pinch point’’, moves steadily back into the beam because of the reduced ionization rate at the expanding beam head and energy loss to the induced electric field. This beam head ’’erosion’’ is modeled by assuming that the axial beam profile is stationary in a reference frame moving with the pinch point. This assumption allows the beam equations to be written in time‐independent form, and radial averaging then yields a set of one‐dimensional ordinary differential equations for the beam radius and energy, the mean pinch force, and the background conductivity. Solution of these equations with appropriate boundary conditions gives both the erosion rate and the beam axial structure. The results of extensive numerical calculations are presented, along with analytic estimates of the erosion rate, degree of current neutralization, and axial scale lengths.
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41.75.Fr Electron and positron beams

Classical diffusion in the presence of an X point

S. P. Auerbach and Allen H. Boozer

Phys. Fluids 23, 2396 (1980); http://dx.doi.org/10.1063/1.862944 (17 pages) | Cited 12 times

Online Publication Date: 21 July 2008

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Classical plasma diffusion is studied in a two‐dimensional system with an X point, the third dimension (the Z axis) being a symmetry direction. Several exact results are presented which give a good qualitative understanding of the diffusive flow in such a system. A soluble model which illustrates these results is also presented. For a scalar resistivity, the results may be summarized as follows: (a) The pressure gradient dP/dΨ (Ψ is the poloidal flux) does not vanish on the separatrix; i.e., the diffusion coefficient D(Ψ) is finite there. (b) Neglecting viscous or inertial effects, the poloidal flow follows lines of constant Hamada angle (defined in the text). This has the consequence that (i) all flow across the separatrix is channeled through the X point, and (ii) the flow velocity along the separatrix is formally infinite. Including viscous or inertial effects would, of course, remove this singularity while modifying the flow only in a small boundary layer region near the separatrix. For a tensor resistivity these conclusions are modified. In particular, a fraction η∥/η⊥ of the particle flow crosses the separatrix through the X point, where η∥ and η⊥ are, respectively, the parallel and perpendicular resistivities.
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52.25.Fi Transport properties
52.30.-q Plasma dynamics and flow
52.55.Dy General theory and basic studies of plasma lifetime, particle and heat loss, energy balance, field structure, etc.

Profile modification by light pressure in plasmas expanding with uniform, time‐dependent temperature

J. R. Sanmartín and J. L. Montañes

Phys. Fluids 23, 2413 (1980); http://dx.doi.org/10.1063/1.862932 (4 pages) | Cited 9 times

Online Publication Date: 21 July 2008

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Profile modification of laser plasmas, in the transition layer at critical density and in the flow on the overdense side, is studied. Assuming isothermal flow and low absorption within the layer, compression transitions are proved impossible and cavities possible only in subsonic flow. The overdense flow adjusts itself for a rarefaction transition in a manner (formation of plateaus, bumps, or cavities) critically dependent on how the (spatially uniform) temperature varies with time. Spherical effects and evidence for the results are considered.
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52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.25.Fi Transport properties
52.25.Kn Thermodynamics of plasmas

High‐energy tail formation by a monochromatic wave in the magnetized plasma

Hirotada Abe, Hiromu Momota, Ryohei Itatani, and Atsushi Fukuyama

Phys. Fluids 23, 2417 (1980); http://dx.doi.org/10.1063/1.862933 (8 pages) | Cited 16 times

Online Publication Date: 21 July 2008

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High‐energy tail formations due to the monochromatic wave in a magnetized plasma are studied numerically and analytically. By calculating the phase space trajectories of 10 000 particles, initially Maxwell‐velocity‐distributed, in the presence of a uniform magnetic field and a sinusoidal wave traveling closely in the perpendicular direction with the frequency of cyclotron harmonics, some properties of particle acceleration are clarified. The acceleration mechanism can be described by a modification of trapping theory and two types of stochastic acceleration. The behavior of the high‐energy tail formation depends on the magnitude of ω/Ω. For small ω/Ω (ω/Ω≲10), the cyclotron harmonics resonance is very important. The ratio of the perpendicular wavelength to the average Larmor radius and the wave amplitude play an important role in determining the ratio of tail to the bulk portion.
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52.20.Dq Particle orbits
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.50.Gj Plasma heating by particle beams
52.65.-y Plasma simulation

Study of plasma density fluctuations by the correlation of crossed CO2 laser beams

C. M. Surko and R. E. Slusher

Phys. Fluids 23, 2425 (1980); http://dx.doi.org/10.1063/1.862934 (15 pages) | Cited 64 times

Online Publication Date: 21 July 2008

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A technique is described which uses correlation of the forward scattering from two intersecting laser beams to measure the spatial distribution ñ(r) of density fluctuations in a plasma directly. Model calculations are presented for the case of low frequency density fluctuations in a tokamak plasma, and experimental results are described for fluctuations in the Alcator A tokamak. Other potential uses of the crossed‐beam correlation technique are discussed such as measurement of the nonequal time correlation function which can yield information about the propagation velocity of the density fluctuations.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Kn Thermodynamics of plasmas
52.25.Gj Fluctuation and chaos phenomena
52.55.Fa Tokamaks, spherical tokamaks
52.55.Hc Stellarators, torsatrons, heliacs, bumpy tori, and other toroidal confinement devices

Simulation of cyclotron wave growth in a helical slow wave structure

R. J. Faehl, B. S. Newberger, and B. B. Godfrey

Phys. Fluids 23, 2440 (1980); http://dx.doi.org/10.1063/1.862945 (14 pages) | Cited 13 times

Online Publication Date: 21 July 2008

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Growth of large amplitude coherent cyclotron waves on unneutralized relativistic electron beams has been studied analytically and numerically. The mechanism for growth is the unstable coupling of helical waveguide modes with relativistic electron beam cyclotron waves. Approximate analytic growth rates are found to be in good agreement with the exact numerical solution of the linearized plasma equations on a self‐consistent cylindrical beam equilibrium. Particle simulations performed in cylindrical geometry quantitatively confirm the theory. The calculations were conducted in both an infinite medium and realistically terminated configuration. In the latter, matched impedances on the helix were required to reduce transients and unwanted reflections to tolerable levels. Saturation in both cases is due either to convection or, in sufficiently long waveguides, growth of the wave until it physically intersected the helix.
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52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.40.Fd Plasma interactions with antennas; plasma-filled waveguides

Integral equation analysis of drift wave eigenmodes in a sheared slab geometry

W. M. Tang, G. Rewoldt, and E. A. Frieman

Phys. Fluids 23, 2454 (1980); http://dx.doi.org/10.1063/1.862946 (7 pages) | Cited 8 times

Online Publication Date: 21 July 2008

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The derivation of the appropriate form for the integral eigenmode equation governing both electron and ion drift waves of arbitrary radial wavelengths in a sheared slab is presented. The solutions to this equation provide useful information regarding the absolute stability of universal modes and ion‐temperature‐gradient driven modes for arbitrary wavelengths, and particularly for short wavelengths.
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52.35.Kt Drift waves

Nonlinear effects on the mode conversion of upper‐hybrid waves

Merit Shoucri and H. H. Kuehl

Phys. Fluids 23, 2461 (1980); http://dx.doi.org/10.1063/1.862947 (11 pages) | Cited 13 times

Online Publication Date: 21 July 2008

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A simple model is presented which is capable of describing the nonlinear field across the upper‐hybrid resonance layer, its time evolution and mode conversion. In the electrostatic approximation, when the density gradient scale length is small compared with the incident wave wavelength, the fields are governed by a driven nonlinear Schrödinger equation. It is found that the nonlinearity due to the ponderomotive force produces an enhancement and a spreading of the Bernstein wave accompanied by a flattening of the density profile. Mode conversion efficiencies as high as 200% of those of the linear regime are reached. The model shows the importance of nonlinearity in the analysis of mode conversion in ionospheric and laboratory, as well as fusion plasmas.
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52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.50.Gj Plasma heating by particle beams

Effect of a dc electric field on the trapping dynamics of a cold electron beam

G. J. Morales

Phys. Fluids 23, 2472 (1980); http://dx.doi.org/10.1063/1.862948 (13 pages) | Cited 8 times

Online Publication Date: 21 July 2008

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The self‐consistent modification of the trapping dynamics of a low density cold electron beam due to the external application of a dc electric field is considered. For dc fields smaller than the peak amplitude of the saturated beam‐plasma instability, the beam energy remains clamped while the wave amplitude grows secularly. Large traveling potential wells appear and create strongly focused charge clumps. By considering the role of wave dissipation, an exact dynamic Bernstein–Greene–Kruskal equilibrium is found analytically. It consists of a singular charge clump which propagates through the medium at constant velocity even though a dc field is present. The numerical study of the basic equations shows that the system evolves asymptotically to this singular state. A variety of experimentally relevant properties associated with the trapping dynamics is investigated, including the stability of the dynamic nonlinear equilibrium to sideband growth.
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52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.40.Mj Particle beam interactions in plasmas

Alfvén‐ion‐cyclotron instability in mirror machines

Duncan C. Watson

Phys. Fluids 23, 2485 (1980); http://dx.doi.org/10.1063/1.862949 (8 pages) | Cited 11 times

Online Publication Date: 21 July 2008

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The Alfvén‐ion‐cyclotron instability is studied for finite mirror‐confined plasmas with high beta without field reversal. Variation perpendicular to field lines is modeled by an effective k⊥. Variation along a representative field line is treated using the Wentzel‐Kramer‐Brillouin approximation in two ways. First, the local dispersion relation is expanded about a wavenumber and frequency corresponding to absolute instability at the machine midplane. This yields a parabolic k∥(s) and a frequency correction. Second, the local dispersion relation is evaluated exactly as a function of position, and the appropriate phase‐integral condition is used to fix the frequency. This condition is chosen using a generalized WKB formulation which is outlined. The two ways of obtaining the mode frequency agree closely. Stability boundaries are drawn in β⊥−β∥ space for two representative finite plasmas. The long thin approximation is used to model finite‐beta well deepening. For ease of computation, the bi‐Maxwellian ion velocity distribution is used. At high β, the stability boundaries are affected by the appearance of an additional root, with a larger parallel wavenumber and a lower frequency.
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52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.55.Jd Magnetic mirrors, gas dynamic traps

Fluid theory of tearing instabilities

A. B. Hassam

Phys. Fluids 23, 2493 (1980); http://dx.doi.org/10.1063/1.862950 (5 pages) | Cited 38 times

Online Publication Date: 21 July 2008

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A fluid theory of tearing instabilities is presented. Recently derived fluid equations, which have the feature of describing adiabatic electron dynamics more completely than the usual transport equations, are employed for this theory. The temperature gradient driven self‐filamentation of a plasma in a uniform magnetic field is described. Temperature gradient driven and magnetically driven ’’collisional’’ and ’’semicollisional’’ drift‐tearing modes are also derived. A comparison with kinetic theories is made; the comparison suggests that the neglect of electron‐electron collisions in kinetic theories of tearing may lead to an overestimate, of appreciable magnitude, of the relative importance of the temperature gradient free energy in driving tearing modes.
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52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Kt Drift waves
52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)

Solitary plasma hole via ion‐vortex distribution

H. Schamel and S. Bujarbarua

Phys. Fluids 23, 2498 (1980); http://dx.doi.org/10.1063/1.862951 (2 pages) | Cited 65 times

Online Publication Date: 21 July 2008

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The first analytical solution of the trapped ion‐vortex state known since the early days of computer simulations is presented. It appears as a nonlinear saturated state of the ion‐ion two‐stream instability and represents, macroscopically, a plasma (ion) hole moving near the ion thermal velocity. Both electron and ion densities are locally depressed.
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52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)

Simulation studies of the collisionless tearing instabilities

I. Katanuma and T. Kamimura

Phys. Fluids 23, 2500 (1980); http://dx.doi.org/10.1063/1.862952 (12 pages) | Cited 19 times

Online Publication Date: 21 July 2008

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Collisionless tearing instabilities and the consequent enhanced transport are investigated theoretically and also numerically, using a two‐and‐one‐half‐dimensional particle simulation code in a slab geometry. The effects of electrostatic fields on the instability are also considered. The initial current is found to diffuse along the perturbed magnetic field lines, the observed diffusion along the perturbed magnetic field lines, the observed diffusion coefficient being in good agreement with the theoretical prediction. The growth of the instability is observed to divide into three phases; a linearly unstable phase, a quasi‐stable phase, and a nonlinear phase similar to the Rutherford phase. Electrostatic effects have a tendency to enhance the tearing mode growth rate. In multi‐mode tearing, a coalescence of magnetic island is observed.
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52.65.-y Plasma simulation
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
94.30.cq MHD waves, plasma waves, and instabilities

A model of anomalous absorption, backscatter, and flux limitation in laser‐produced plasmas

D. G. Colombant and Wallace M. Manheimer

Phys. Fluids 23, 2512 (1980); http://dx.doi.org/10.1063/1.862953 (17 pages) | Cited 17 times

Online Publication Date: 21 July 2008

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Fluid simulations of laser light absorption and backscatter for planar targets are presented for various laser irradiances, wavelengths, target materials, laser pulse lengths, and simulated prepulse conditions. Physical processes included in the model are inverse bremsstrahlung, resonant absorption, absorption by ion‐acoustic fluctuations, and Brillouin backscatter. For the anomalous processes, self‐consistent transport coefficients are derived and used throughout the time‐dependent, one‐dimensional code. Flux limitation is thus taken into account as a result of the physical processes included. Interplay between the various absorption mechanisms and backscatter are uncovered in this study. Comparisons with experiments are presented and suggestions for further experiments are made.
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52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.65.-y Plasma simulation

Some conservation properties of linearized particle codes

Bruce I. Cohen, S. P. Auerbach, J. A. Byers, and H. Weitzner

Phys. Fluids 23, 2529 (1980); http://dx.doi.org/10.1063/1.862954 (9 pages) | Cited 8 times

Online Publication Date: 21 July 2008

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Conservation laws are derived which are appropriate for use in linearized particle simulation codes. A continuity equation describing mass or charge conservation and an extended Poynting theorem describing energy flow are obtained for general curvilinear coordinate systems. These conservation equations are expressed in terms of quantities readily calculable in a particle code, serve to quantitatively assess the validity and precision of code results, and provide valuable insight into the physics being studied. A conserved quantity related to the system energy, rather than a Poynting theorem, is derived from a Lagrangian formulation. It is bilinear in first‐order quantities but is not attractive for implementation as a diagnostic in a linearized particle simulation.
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52.65.-y Plasma simulation

Influence of wall impedance on the electron cyclotron maser instability

Han S. Uhm and Ronald C. Davidson

Phys. Fluids 23, 2538 (1980); http://dx.doi.org/10.1063/1.862955 (9 pages) | Cited 18 times

Online Publication Date: 21 July 2008

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The influence of finite‐wall impedance on the cyclotron maser instability is investigated for a hollow electron beam. The stability analysis is carried out within the framework of the linearized Vlasov–Maxwell equations, assuming that the beam thickness is much less than the mean radius of the beam. The formal dispersion relation for azimuthally symmetric electromagnetic perturbations including the important influence of arbitrary wall impedance is obtained. One of the most important features of the analysis is that, for a purely resistive wall, the instability growth rate is substantially reduced by a very small wall resistivity. Moreover, the range of axial wavenumbers corresponding to instability increases rapidly as the wall resistivity is increased. Cyclotron maser stability properties for a dielectric loaded waveguide are also investigated. For an appropriate choice of the dielectric constant ϵ and the thickness of the dielectric material, it is shown that the instability bandwidth can be more than double that for a perfectly conducting waveguide.
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84.40.Az Waveguides, transmission lines, striplines

Observations of neoclassical and anomalous resistivity in toroidal discharges

J. F. Etzweiler and D. A. Brouchous

Phys. Fluids 23, 2547 (1980); http://dx.doi.org/10.1063/1.862956 (9 pages) | Cited 3 times

Online Publication Date: 21 July 2008

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Plasma resistivity measurements parallel to the magnetic field have been made on the Wisconsin supported octupole and the Wisconsin levitated octupole. Plasmas ranged in density from 108 to 1012 cm−3 and varied from highly collisionless to highly collisional. The measured resistivity was found to agree with neoclassical resistivity theory in the collisional and transition regimes. Highly collisionless plasmas were found to have anomalously high resistivity which obeyed the Te1/2/ne scaling of the transition regime.
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52.25.Fi Transport properties
52.55.Jd Magnetic mirrors, gas dynamic traps
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