摘要 :
The spectrum of axisymmetric torsional Alfven waves propagating in a cylindrical, non-uniform, resistive plasma waveguide has been analysed by a method of singular perturbations. A simple condition has been derived which predicts ...
展开
The spectrum of axisymmetric torsional Alfven waves propagating in a cylindrical, non-uniform, resistive plasma waveguide has been analysed by a method of singular perturbations. A simple condition has been derived which predicts whether the spectrum is continuous or discrete under given physical conditions. Application of this result to resolve an apparent discrepancy in experimental observations is briefly discussed. (Atomindex citation 09:356163)
收起
摘要 :
Numerical calculations of magnetoacoustic resonant phenomena in a plasma containing two species of ions have been made for a cylindrical plasma with a model which includes the effects of collisional damping and radial non-uniformi...
展开
Numerical calculations of magnetoacoustic resonant phenomena in a plasma containing two species of ions have been made for a cylindrical plasma with a model which includes the effects of collisional damping and radial non-uniformities in temperature and number density. At sufficiently high temperatures two frequencies are predicted at which magnetoacoustic resonances for the first radial mode will occur. These are expected from considerations of the effects of the ion-ion hybrid resonance. (Atomindex citation 09:356122)
收起
摘要 :
The one-dimensional self-similar motion of an initially cold, half-space plasma of electron density n sub(0), produced by the (anomalous) absorption of a laser pulse of irradiation phi = phi sub(0)t/tau(0(<)t(<=)tau) at the critical density n sub(c), is considered; the analysis, which allows for electron heat conduction and ion-electron energy exchange, involves three dimensionless numbers: epsilon identical to n sub(c)/n sub(0) assumed small, Z sub(i) (ion charge number), and a parameter alpha varies as (nsub(0)sup(2)tau/phisub(0))sup(2/3). For alpha(<<)1 a weak discontinuity develops, separating a thermal wave (where convection is negligible) moving into the undisturbed plasma, from a much thinner isothermal flow expanding into the vacuum. For 1(<<)alpha(<<)epsilonsup(-4/3) there is an isentropic compression flow between a shock, blounding the undisturbed plasma, and a very thin transition layer bounding an expansion flow, much larger in extent than the compression region. In both regimes the critical plane lies far in the expansion tail. The results break down when the density is so small that the plasma becomes collisionless. The analysis is also invalid for alpha too small. Using results previously found for alpha(>>)epsilon sup(-4/3), a qu...
展开
The one-dimensional self-similar motion of an initially cold, half-space plasma of electron density n sub(0), produced by the (anomalous) absorption of a laser pulse of irradiation phi = phi sub(0)t/tau(0(<)t(<=)tau) at the critical density n sub(c), is considered; the analysis, which allows for electron heat conduction and ion-electron energy exchange, involves three dimensionless numbers: epsilon identical to n sub(c)/n sub(0) assumed small, Z sub(i) (ion charge number), and a parameter alpha varies as (nsub(0)sup(2)tau/phisub(0))sup(2/3). For alpha(<<)1 a weak discontinuity develops, separating a thermal wave (where convection is negligible) moving into the undisturbed plasma, from a much thinner isothermal flow expanding into the vacuum. For 1(<<)alpha(<<)epsilonsup(-4/3) there is an isentropic compression flow between a shock, blounding the undisturbed plasma, and a very thin transition layer bounding an expansion flow, much larger in extent than the compression region. In both regimes the critical plane lies far in the expansion tail. The results break down when the density is so small that the plasma becomes collisionless. The analysis is also invalid for alpha too small. Using results previously found for alpha(>>)epsilon sup(-4/3), a qualitative discussion of how plasma behavior changes with alpha, is given. (Atomindex citation 10:419696)
收起
摘要 :
The forced radial magneto-acoustic oscillations in a partially-ionized, low- beta plasma column with non-uniform densities, temperature and axial current are investigated theoretically. By using a method of successive approximatio...
展开
The forced radial magneto-acoustic oscillations in a partially-ionized, low- beta plasma column with non-uniform densities, temperature and axial current are investigated theoretically. By using a method of successive approximations to include resistive and viscous dissipations, the description of these oscillations has been reduced to the solution of a second order differential equation in the axial magnetic field disturbance bsub(z)(r) . A detailed numerical solution is presented for a case where the axial current is uniform and the dissipation is resistive. It is shown that the steady axial current enhances the magnetic field amplitudes at magneto-acoustic resonance. (Atomindex citation 09:356162)
收起
摘要 :
A general theory of relativistic nonlinear electromagnetic waves in a cold electron plasma is presented. Three modes of propagation are analyzed: (1) longitudinal waves, (2) transverse circularly polarized waves, and (3) coupled t...
展开
A general theory of relativistic nonlinear electromagnetic waves in a cold electron plasma is presented. Three modes of propagation are analyzed: (1) longitudinal waves, (2) transverse circularly polarized waves, and (3) coupled transverse-longitudinal waves. The dispersion relations are obtained. A number of relativistic and nonlinear effects are discussed.
收起
摘要 :
Trapped electron modes in stellarators can be more unstable than those in tokamaks. They could be easier to detect in a stellarator and may be responsible for anomalous losses in the low collisionality regime. 5 refs., 1 fig. (ERA...
展开
Trapped electron modes in stellarators can be more unstable than those in tokamaks. They could be easier to detect in a stellarator and may be responsible for anomalous losses in the low collisionality regime. 5 refs., 1 fig. (ERA citation 15:011943)
收起
摘要 :
The magnetoacoustic modes are excited in the FIVA device at low power level. The results are in good agreement with the predictions based on the excitation of the fast magnetoacoustic wave in the transversely magnetized wave-guide...
展开
The magnetoacoustic modes are excited in the FIVA device at low power level. The results are in good agreement with the predictions based on the excitation of the fast magnetoacoustic wave in the transversely magnetized wave-guide. The resonance quality factor, antenna-mode coupling and loading resistance are measured. The results indicate that a substantial part of the power available at the antenna can be deposited in the magnetoacoustic mode. (Atomindex citation 11:560894)
收起
