Recent results in the theory of turbulent momentum transport and origins intrinsic rotation are summarized. Special attention is focused on aspects critical to rotation, namely residual stress edge toroidal flow velocity pinch. Novel include a systematic decomposition physical processes which drive calculation external torque necessary hold plasma stationary against stress, simple model net scaling recovers salient features experimental trends elucidation impact particle flux Specific...

In this paper, two mode-coupling analyses for the nonlinear excitation of geodesic acoustic modes (GAMs) in tokamak plasmas by drift waves are presented. The first approach is a coherent parametric process, which leads to three-wave resonant interaction. This investigation allows and GAMs have comparable scales. second uses wave-kinetic equations waves, then couples GAMs. requires that GAM scale length be large compared wave packet associated with waves. resonance conditions these cases lead...

Formation of a density blob and its motion in the edge scrape-off layer (SOL) tokamak plasma have been simulated using two-dimensional, two-field, fluid model equations. The simulation results show that blobs form or edge-to-SOL transition region where poloidal velocity shear is maximum. From numerical data, condition for formation has obtained. Dynamics detached SOL regions studied. It observed not all are capable ejection deep into SOL. A their also discussed. Radial particle transport...

Instabilities of dust acoustic waves in a plasma with significant background pressure neutrals have been investigated. A long wavelength mode is found to be unstable due recombination electrons and ions on the surface particles. At short wavelengths, dissipative instability driven by relative drift between particles important. Nonlinearly, modes lead formation $K\ensuremath{-}dV$ solitons whereas end dominated modulational instabilities.

The formation of coherent structures by two-dimensional interchange turbulence in the scrape-off layer (SOL) tokamak plasmas and their subsequent contribution to anomalous plasma transport has been studied recent years using electron continuity current balance equations. In this paper, it is demonstrated that inclusion energy equation simulations changes nature a significant manner gives results which are better agreement with experiments. Specifically, observed radial potential gradients...

Particle and energy transport in the tokamak edge barrier is analyzed presence of magnetic field perturbations from external resonant coils. In recent experiments such coils have been verified as an effective tool for mitigation edge-localized modes type I. The observed reduction density plasmas low collisionality explained by generation charged particle flows along perturbed lines. increase electron ion temperatures interpreted perpendicular neoclassical with decreasing nonlocality parallel...

To understand the L–H transition, one has to identify modes be stabilized at edge of L-mode plasmas, roughly from ρ = 0.7 last closed flux surface. address this issue, realistic tokamak parameters inspired by three different L-modes DIII-D and Tore Supra have been investigated with a gyrokinetic code GENE (Jenko et al 2000 Phys. Plasmas 7 1904). Former fluid theories for such predict resistive ballooning (RBMs) unstable (Rogers 1998 Rev. Lett. 81 4396). In paper, linear simulations...

A novel two-dimensional (2D) fluid model is proposed for investigating flux-driven plasma turbulence in the tokamak edge and scrape-off layer (SOL). Unlike most previous simulations of this region, 2D treats two regions a consolidated manner with smooth transition region between. The unified simpler less computer intensive than 3D models, but captures features SOL turbulence. It also illustrates influence on transport, something not captured by earlier simulations. Existence an equilibrium...

Charged particle losses at the plasma edge affected by resonant magnetic perturbations (RMP) are considered taking into account electron and ion flows both parallel perpendicular to perturbed field lines. Calculations done for H-mode plasmas of low collisionality, i.e., under conditions where significant pump out particles has been observed in experiments on DIII-D tokamak [J. Luxon, Nucl. Fusion 42, 614 (2002)] with RMP from I-coils. It is demonstrated that flux, arising stochastization due...

We investigate nonlinear stationary structures in a system of coupled equations describing drift wave turbulence and associated self-consistent zonal flows. The short-scale is described by kinetic equation for the action density waves, whereas longer-scale flows are dynamic m = n 0 (toroidally poloidally symmetric) component potential. Nonlinear moving frame can be obtained retaining novel effects with `trapped' `untrapped' trajectories. show that self-consistently sustain coherent, radially...

Two-dimensional (2D) interchange turbulence in the scrape-off layer of tokamak plasmas and their subsequent contribution to anomalous plasma transport has been studied recent years using electron continuity, current balance, energy equations. In this paper, numerically it is demonstrated that inclusion ion equation simulation changes nature turbulence. Finite temperature reduces floating potential by about 15% compared with cold approximation also radial electric field. Rotation blobs at an...

Analytical investigations of several linear and non-linear features ETG turbulence are reported. The theory includes effects such as finite beta induced electromagnetic shielding coupling to electron magnetohydrodynamic modes whistlers. It is argued that non-linearity, transport dominated by radially extended called `streamers'. A mechanism generating streamers based on a modulational instability the also presented. saturation levels using Kelvin-Helmholtz secondary calculated thermal due estimated.

Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence described by a wave-kinetic equation for action density of mode, and longer scale zonal mode dynamic m = n 0 component potential. Two populations trapped untrapped drift wave trajectories are shown to exist moving frame reference. This novel effect leads nonlinear structures. It that can self-consistently sustain coherent, radially propagating...

This paper describes an in-house designed large Electron Energy Filter (EEF) utilized in the Large Volume Plasma Device (LVPD) [S. K. Mattoo, V. P. Anita, L. M. Awasthi, and G. Ravi, Rev. Sci. Instrum. 72, 3864 (2001)] to secure objectives of (a) removing presence remnant primary ionizing energetic electrons non-thermal electrons, (b) introducing a radial gradient plasma electron temperature without greatly affecting profile density, (c) providing control on scale length temperature. A set...

On the basis of three-dimensional nonlinear magnetohydrodynamic simulations, we propose a new dynamical process leading to stochastization magnetic fields during an edge pedestal collapse. Primary tearing modes are shown grow by extracting kinetic energy unstable ballooning modes, eventually island overlap. Secondary which generated through coherent interaction between adjacent play key role in this process, mediating transfer primary and modes. Explicit calculations parallel loss stochastic...

Abstract We perform a computational study of the role zonal flows in edge pedestal collapse on basis nonlinear three-field reduced magnetohydrodynamic (MHD) model. A dramatic change dynamics takes place when ideal ballooning modes are completely stabilized. Analyses show that new instability is developed due to strong excitation vorticity, resulting series secondary crashes. The presence subsidiary bursts after main crash increases effective time and energy loss. These simulation results...

The time and space resolved emission profiles of the CII line from laser-blow-off (LBO) plumes multilayered LiF-C thin film have been investigated using a laser-induced forward transfer technique. evolution features 426.7 nm were studied in different ambient environments ranging high vacuum to 3 mbar argon pressures at various fluences ablating laser. It was found that many plasma plume generated by LBO method resemble created conventional laser produced plasma; however, few differences...

The evolution features of electrons and ions generated by laser-blow-off (LBO) a multi-component LiF-C target have been studied using optical spectroscopic Langmuir probe (LP) techniques. In addition to the hydrodynamic plume splitting, multi-peak structures are reported in temporal profiles measured LP. We propose that observed multi-peaks arise due mass dependent expansion velocity different elements present plasma plume. evolutions electron density temperature vacuum 10−2 mbar argon...

This paper presents a theory of coupled whistler (W) and electron temperature gradient (ETG) mode using two-fluid model in high beta plasma. Non-adiabatic ion response, parallel magnetic field perturbation (δBz), perpendicular flutter (δB⊥), collisions are included the treatment theory. A linear dispersion relation for whistler-electron (W-ETG) is derived. The numerical results obtained from this compared with experimental observed large volume plasma device (LVPD) [Awasthi et al., Phys....

A simple generic one-dimensional continuum model of driven dissipative systems is proposed to explain self-organized bursty heat transport in tokamaks. Extensive numerical simulations this reproduce many features present day tokamaks such as submarginal temperature profiles, intermittent events, $1/f$ scaling the frequency spectra, propagating fronts, etc. This utilizes a minimal set phenomenological parameters, which may be determined from experiments and/or simulations. Analytical and...