Toroidal Plasma Rotation in the Princeton Large Torus Induced by Neutral-Beam Injection

Suckewer, S.; Eubank, H. P.; Goldston, Robert James; Hinnov, E.; Sauthoff, N.

doi:10.1103/physrevlett.43.207

Cited by 115 publications

(78 citation statements)

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“…3 Many experiments and computer experiments have been carried out 1,4 to test its novel predictions, e.g., that there is a hexatic phase be- tween the solid and the isotropic liquid, and that the transitions are thermodynamically continuous, Most recent computer simulations, e.g., on the Lennard-Jones system at constant pressure, 5 and r~n systems with n = 12, 6 » 7 n = 3, 8 ' 9 and w = l, 10 show a first-order transition and no hexatic phase. Freezing parameters such as the entropy change (AS/k B ) 6 " 10 and the structure factor peak near freezing 7 ' 9,n * 12 are close to 0.3 and 5.0, re-…”

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confidence: 90%

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Magnetohydrodynamic Instability with Neutral-Beam Heating in the ISX-BTokamak

et al. 1982

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This paper describes observations of magnetohydrodynamic instability with neutralbeam heating in the ISX-.B tokamak and the theory specifically developed to support these experiments. The observed magnetohydrodynamic activity is explained by the resistive model presented but is not responsible for the observed degradation of confinement. Increasingly important n > 1 pressure-driven modes are predicted by the theory for the higher experimental pp values, but there is no experimental verification of their presence.

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confidence: 90%

“…From B p , mode rotation is the reverse of that in OH plasmas, possibly because of toroidal rotation driven by the coinjected neutral beams. 6 The large X signals are from within q ~ 1 and are due to a large m = 1 mode there. Rotation of this m = 1 structure is also reversed.…”

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Magnetohydrodynamic Instability with Neutral-Beam Heating in the ISX-BTokamak

et al. 1982

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“…In the above mentioned studies the inertial-force flow term ρ(v · ∇)v is neglected in the equation of momentum conservation. For ion flow velocities of the order of 100 Km/m, which have been observed in neutral-beam-heating experiments [6,7,8] the term ρ(v · ∇)v can not be considered negligible. Therefore, it is worthwhile to investigate the nonlinear resistive equilibrium, in particular to address the following issues: (a) the impact of the non-linear flow in the Pfirsch-Schlüter diffusion, and (b) the existence of resistive equilibria, in particular equilibria with σ = σ(ψ).…”

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On resistive magnetohydrodynamic equilibria of an axisymmetric toroidal plasma with flow

Throumoulopoulos

Tasso

2000

J. Plasma Phys.

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It is shown that the magnetohydrodynamic equilibrium states of an axisymmetric toroidal plasma with finite resistivity and flows parallel to the magnetic field are governed by a second-order partial differential equation for the poloidal magnetic flux function ψ coupled with a Bernoulli type equation for the plasma density (which are identical in form to the corresponding ideal MHD equilibrium equations) along with the relation ∆ ⋆ ψ = V c σ. (Here, ∆ ⋆ is the Grad-Schlüter-Shafranov operator, σ is the conductivity and V c is the constant toroidal-loop voltage divided by 2π). In particular, for incompressible flows the above mentioned partial differential equation becomes elliptic and decouples from the Bernoulli equation [H. Tasso and G. N. Throumoulopoulos, Phys. Plasmas 5, 2378 (1998)]. For a conductivity of the form σ = σ(R, ψ) (R is the distance from the axis of symmetry) several classes of analytic equilibria with incompressible flows can be constructed having qualitatively plausible σ profiles, i.e. profiles with σ taking a maximum value close to the magnetic axis and a minimum value on the plasma surface. For σ = σ(ψ) consideration of the relation ∆ ⋆ ψ = V c σ(ψ) in the vicinity of the magnetic axis leads therein to a proof of the non-existence of either compressible or incompressible equilibria. This result can be extended to the more general case of non-parallel flows lying within the magnetic surfaces.

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“…A^ai WN0A n ' (2) The results of the calculation in the case that the density and temperature of protons are the same as those of electrons are shown in Fig. 3; the proton temperature has a noticeable effect on the intensity ratio for low-density plasma (n e < 3x 10 13 cm -3 ).…”

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Intensity measurements of the forbidden line 975 Åof Fe xviii: A transition sensitive to proton temperature

et al. 1986

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The intensity of the Fexvm forbidden line at 975 A (2s 2 2p 52 Pi/ 2 -+ 2s 2 2p 52 Py 2 ) relative to that of an allowed line at 94 A (2s2p 62 S\/2~^ 2s 2 2p 52 Py 2 ) was measured during ion-Bernstein-wave heating in tokamak discharges. The results at low electron densities (n e < 3x 10 13 cm -3 ) indicated a noticeable effect of proton collisions on the intensity of the forbidden line. Calculation also shows the importance of proton collision to the Fexvm forbidden-line intensity.PACS numbers: 52.20.Hv, 32.30.Rj, 52.25.Nr Forbidden transitions in the ground-state configurations of highly ionized atoms have been studied extensively in tokamak plasmas. In addition to providing information on fundamental aspects of atomic physics, the spectra of forbidden lines have useful diagnostic applications to plasmas because their wavelengths are longer than those of the optically allowed transitions. 1 "" 4 In this paper, we present the effect of proton collisions on the intensity of a forbidden line of Fe xvm at 975 A relative to that of an allowed line at 94 A during auxiliary heating. Calculations of the intensity ratio of the 975-A line to the 94-A line as a function of the temperature and density of electrons and protons are presented and compared with the measurements. The line ratio has been found to be sensitive to the proton temperature at electron densities below 3x 10 13 cm" 3 .The state populations for the 2s 2 2p k configurations were discussed by Feldman and co-workers. 5 " 7 These authors showed that the populations of the metastable levels may be in a close equilibrium with that of the ground state at high densities. But, in the case of plasmas with electron densities lower than several 10 13 cm -3 , which is in the typical operating range of tokamaks, the population of the upper state for a forbidden transition is far from equilibrium with that of the ground state. It strongly depends on the balance of the radiative decay rate and the collisional rates of electrons and especially of protons.The absolute radiances of the Fe xvm forbidden line o o at 975 A and the allowed line at 94 A were measured by Suckewer and Hinnov in the PLT (Princeton Large Torus). 8 Comparison of the observed intensity ratios with the calculated ones (for the measured electron density) indicated that inclusion of the proton collisions made the agreement between theory and experiment worse. They concluded that the influence of proton collisions on the forbidden-line intensity was uncertain in the Ohmic-heating discharges but it might become quite significant during additional heating.Measurements of the time evolution of the radiances of Fe xvm lines were carried out during an ion-Bernstein-wave-heating (IBWH) experiment on the JIPP T-II-U tokamak at the Institute of Plasma Physics, Japan. 9 The plasma parameters before the heating were 7^-110 kA, £, = 18 kG, ^ = 1.5xl0 13 cm" 3 , and r e (0) = 700eV. An rf power of 80 kW at 40 MHz was applied for 30 ms. A 2-m grazing-incidence monochromator which viewed the plasma along a central...

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Toroidal Plasma Rotation in the Princeton Large Torus Induced by Neutral-Beam Injection

Cited by 115 publications

References 6 publications

Magnetohydrodynamic Instability with Neutral-Beam Heating in the ISX-BTokamak

Magnetohydrodynamic Instability with Neutral-Beam Heating in the ISX-BTokamak

On resistive magnetohydrodynamic equilibria of an axisymmetric toroidal plasma with flow

Intensity measurements of the forbidden line 975 Åof Fe xviii: A transition sensitive to proton temperature

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