Systematic analysis of numerical simulations of two-dimensional magnetohydrodynamic turbulence reveals the presence of a large number of X-type neutral points where magnetic reconnection occurs. We examine the statistical properties of this ensemble of reconnection events that are spontaneously generated by turbulence. The associated reconnection rates are distributed over a wide range of value...

If taken into account, the transmission of the particle-scattering turbulence –in addition to just the particles– through the shock front can change the effective compression ratio felt by the accelerating particles significantly from the compression of the underlying plasma. This can lead to significantly harder energy spectra than what are traditionally predicted assuming frozen-in turbulence...

The first toroidal, gyrokinetic, electromagnetic simulations of small scale plasma turbulence are presented. The turbulence considered is driven by gradients in the electron temperature. It is found that electron temperature gradient (ETG) turbulence can induce experimentally relevant thermal losses in magnetic confinement fusion devices. For typical tokamak parameters, the transport is essenti...

A relationship between power anisotropy and wavevector anisotropy in turbulent fluctuations is derived. This can be used to interpret plasma turbulence measurements, for example in the solar wind. If fluctuations are anisotropic in shape then the ion gyroscale break point in spectra in the directions parallel and perpendicular to the magnetic field would not occur at the same frequency, and sim...

Cluster plasmas are magnetised already at very low magnetic field strength. Low collisionality implies that conservation of the first adiabatic invariant results in an anisotropic viscous stress (Braginskii viscosity) or, equivalently, anisotropic plasma pressure. This triggers firehose and mirror instabilities, which have growth rates proportional to the wavenumber down to scales of the order ...

Incompressible magnetohydrodynamics is often assumed to describe solar wind turbulence. We use extended self-similarity to reveal scaling in the structure functions of density fluctuations in the solar wind. The obtained scaling is then compared with that found in the inertial range of quantities identified as passive scalars in other turbulent systems. We find that these are not coincident. Th...

where θ is the density of impurities, μθ the collisional diffusivity, and ζ = mθ qθ e mi ρs Ln the influence of inertia, which enters via the polarization drift. The latter makes the flow compressible, consequently for ideal (massless) impurities, ζ = 0 and advection is due to the incompressible electric drift only. In all cases the impurity density is assumed to be so low compared to the bulk ...

Comparative studies were carried out to elucidate the most essential parameter(s) for control of density profiles in LHD heliotron and JT-60U tokamak plasmas. Different collisionality dependence was found between two devices. Change of fluctuation property was observed at different density profile in both devices in plasma core region. In JT-60U, increase of radial correlation length was observ...

The particle and energy transport was analyzed for different regions and regimes of the plasma in tokamak with special attention for ITER. For the particle transport in the tokamak edge plasma was obtained results useful for the qualitative cross-check of the numerical models of the first principle simulations, including ITER, as well as in the elaboration of the simplified, reduced models of t...