<i>Plasma Physics for Nuclear Fusion</i>

Miyamoto, Katsuhiko; Dewar, R. L.

doi:10.1063/1.2914166

Cited by 185 publications

(181 citation statements)

References 0 publications

Supporting

Mentioning

178

Contrasting

Order By: Relevance

“…It is difficult to suppress these instabilities and can cause much anomalous diffusion. 2 These instabilities have been first studied by Kadomstev and Pogutse 3 and experimental evidence of these modes has also been found in linear plasma devices. 4 Substantial efforts have been made to understand microinstabilities in tokamak geometries.…”

Section: Introductionmentioning

confidence: 92%

Dissipative trapped-electron instability in quasihelically symmetric stellarators

Rafiq

Hegna

2006

Physics of Plasmas

View full text Add to dashboard Cite

The linear electrostatic dissipative trapped-electron mode is investigated in a quasihelically symmetric ͑QHS͒ stellarator and a configuration whose symmetry is spoiled by the addition of a mirror contribution to the magnetic spectrum. The effect of the trapped electrons is accounted for using the drift kinetic equation with an energy-dependent Krook collision operator and an effective collision frequency giving the rate of detrapping. The ballooning mode formalism and Wentzel-Kramers-Brillouin type boundary conditions are used to solve an eigenvalue problem for a drift wave equation with nearly adiabatic electrons in a fully three-dimensional magnetohydrodynamic equilibria. The trapped-electron growth rate is calulated using a perturbative approach. Multiple classes of helically localized and toroidally localized eigenfunctions in the ballooning space are calculated. The results of the QHS configuration is compared and contrasted with the results of the mirror configuration. The helically trapped modes are found to be most destabilizing. In both configurations the magnitude of the linear growth rates are comparable, crudely indicating the same level of anomalous flux as has also been observed in the edge region of experiments.

show abstract

Section: Introductionmentioning

confidence: 92%

Dissipative trapped-electron instability in quasihelically symmetric stellarators

Rafiq

Hegna

2006

Physics of Plasmas

View full text Add to dashboard Cite

show abstract

“…Diamagnetic measurements are commonly used in fusion devices [6] to derive the normalised plasma pressure, or poloidal beta, from the toroidal magnetic flux produced by the plasma, using the equilibrium relation, given here in its simplified form .…”

Section: Introductionmentioning

confidence: 99%

Fast single loop diamagnetic measurements on the TCV tokamak

Moret

Bühlmann

Tonetti

2003

Review of Scientific Instruments

View full text Add to dashboard Cite

Measurement of the plasma generated diamagnetic flux on TCV is used to derive the plasma pressure, as on other magnetic confinement experiments. However specificities of the device make the measurement more difficult: for passive stabilisation of the vertical position of highly elongated plasmas, the vessel has a low electrical resistivity, leading to large image currents in the vessel. For the same reason the plasma must also be kept close to the conducting wall, so that the in-vessel double loop method usually used to compensate for these currents can not be applied. In order to achieve proper compensation, the diamagnetic measurement diagnostic on TCV uses the signal from a single loop wound outside the vessel in combination with appropriate signal processing that accurately matches the fast component of the induced vessel current. This allows extraction of the plasma diamagnetic flux with a remarkable bandwidth, of ~10kHz, and with the required accurate compensation of 0.05mWb out of 2Wb.As a result, rapid changes in plasma pressure can be studied, for example during additional heating power modulation or plasma instabilities such as ELMs.

show abstract

“…Starting with general fluid equations for the particle, momentum, and energy balance for each plasma species, 12,13 …”

Section: A Fluid Equation and Drift Approximationmentioning

confidence: 99%

Revisited global drift fluid model for linear devices

Reiser

2012

Physics of Plasmas

View full text Add to dashboard Cite

The problem of energy conserving global drift fluid simulations is revisited. It is found that for the case of cylindrical plasmas in a homogenous magnetic field, a straightforward reformulation is possible avoiding simplifications leading to energetic inconsistencies. The particular new feature is the rigorous treatment of the polarisation drift by a generalization of the vorticity equation. The resulting set of model equations contains previous formulations as limiting cases and is suitable for efficient numerical techniques. Examples of applications on studies of plasma blobs and its impact on plasma target interaction are presented. The numerical studies focus on the appearance of plasma blobs and intermittent transport and its consequences on the release of sputtered target materials in the plasma. Intermittent expulsion of particles in radial direction can be observed and it is found that although the neutrals released from the target show strong fluctuations in their propagation into the plasma column, the overall effect on time averaged profiles is negligible for the conditions considered. In addition, the numerical simulations are utilised to perform an a-posteriori assessment of the magnitude of energetic inconsistencies in previously used simplified models. It is found that certain popular approximations, in particular by the use of simplified vorticity equations, do not significantly affect energetics. However, popular model simplifications with respect to parallel advection are found to provide significant deterioration of the model consistency. [http://dx

show abstract

Plasma Physics for Nuclear Fusion

Cited by 185 publications

References 0 publications

Dissipative trapped-electron instability in quasihelically symmetric stellarators

Dissipative trapped-electron instability in quasihelically symmetric stellarators

Fast single loop diamagnetic measurements on the TCV tokamak

Revisited global drift fluid model for linear devices

Contact Info

Product

Resources

About