Scaling laws for ion temperature gradient driven turbulence in magnetized toroidal plasmas are derived and compared with direct numerical simulations. Predicted dependences of turbulence fluctuation amplitudes, spatial scales, and resulting heat fluxes on temperature gradient and magnetic field line pitch are found to agree with numerical results in both the driving and inertial ranges. Evidenc...

In gyrokinetic theory, the quadratic nonlinearity is known to play an important role in the dynamics by redistributing (in a conservative fashion) the free energy between the various active scales. In the present study, the free energy transfer is analyzed for the case of ion temperature gradient driven turbulence. It is shown that it shares many properties with the energy transfer in fluid tur...

We report experimental measurements of the axial plasma flow and the parallel ion temperature in a magnetized linear plasma device. We used laser induced fluorescence to measure Doppler resolved ion velocity distribution functions in argon plasma to obtain spatially resolved axial velocities and parallel ion temperatures. We also show changes in the parallel velocity profiles during the transit...

The modi cation of turbulence in the edge plasma of the DIII{D tokamak at the transition from the low to the high mode of con nement is investigated with a phase-contrast imaging diagnostic. The amplitude and radial correlation length of the turbulence in the con nement region decrease at the transition, whereas the decorrelation time increases. The transition model of Biglari, Diamond, and Ter...

Despite of a lot of efforts and interesting results, accretion disk theory is still under development and there are several unknowns: specifically, all available models are in the steady state approximation. In this letter, we investigate unsteady motion, beginning with shock wave–turbulence interaction. Indeed, unsteady flow allows this type of interaction, which in turn results in substantial...

Toroidal rotation is a key part of the design of ITER because of its ability to stabilize resistive wall modes. Understanding of the intrinsic rotation drive in plasmas is important because it will be difficult to externally torque a plasma the size of ITER. This section will cover phenomenology of the toroidal rotation and momentum transport processes. First, a historial understanding of heat ...

This paper reports the results of gyrokinetic simulation studies of ion temperature gradient driven turbulence which investigate the role of non-resonant modes in turbulence spreading, turbulence regulation, and self-generated plasma rotation. Non-resonant modes, which are those without a rational surface within the simulation domain, are identified as nonlinearly driven, radially extended conv...

Plasma turbulence in a linear device is explored for the first time with three-dimensional global two-fluid simulations, focusing on the plasma parameters of the Large Plasma Device. Three instabilities are present in the simulations: the Kelvin-Helmholtz instability, a sheath-driven instability, and a resistive drift wave instability. The Kelvin-Helmholtz mode is shown to dominate the transpor...

Numerical simulations of two-dimensional Magnetohydrodynamic (2D MHD) turbulence reveal the presence of a huge number of sites where magnetic reconnection locally occurs. The properties of this ensemble of reconnection events, that are spontaneously generated by turbulence, have been studied. The associated reconnection rates, computed as the electric field at the neutral points, are broadly di...

Relativistic Astrophysics generates a number of problems where plasma physics plays an essential role. The acceleration of cosmic rays, and of the nonthermal particle distributions present in astrophysical sources of synchrotron radiation, are famous and long standing examples. The acceleration, transport and termination of magnetized relativistic flows emerging from compact objects is an almos...