Microtearing modes and the pedestal
نویسندگان
چکیده
منابع مشابه
Electromagnetic gyro-fluid simulations with BOUT++
Transport at the pedestal top is important for the inter-ELM pedestal dynamics. Linear gyrokinetic analysis of the pedestal during an ELM cycle on MAST has shown kinetic ballooning modes to be unstable at the knee of the pressure profile and in the steep pedestal region whilst microtearing modes (MTMs) and electron temperature gradient modes (ETGs) dominate in the shallow gradient region inboar...
متن کاملKinetic instabilities that limit β in the edge of a tokamak plasma: a picture of an H-mode pedestal.
Plasma equilibria reconstructed from the Mega-Amp Spherical Tokamak have sufficient resolution to capture plasma evolution during the short period between edge-localized modes (ELMs). Immediately after the ELM, steep gradients in pressure, P, and density, n(e), form pedestals close to the separatrix, and they then expand into the core. Local gyrokinetic analysis over the ELM cycle reveals the d...
متن کاملLinear gyrokinetic analysis of a DIII-D H-mode pedestal near the ideal ballooning threshold
Recent advances in GYRO allow simulations to map out the linear stability of many eigenvalues and eigenvectors of the gyrokinetic equation (as opposed to only the most unstable) at low computational cost. In this work, GYRO’s new linear capabilities are applied to a pressure scan about the pedestal region of DIII-D shot 131997. MHD calculations in the infinite-n limit of the ideal ballooning mo...
متن کاملIntermediate-k Density and Magnetic Field Fluctuations During Inter-ELM Pedestal Evolution in MAST
Measurements of local density and magnetic field fluctuations near the pedestal top, conditionally-averaged over the ELM cycle, have been made in MAST. A Doppler backscattering (DBS) system installed at MAST was used to measure intermediate-k (k⊥ρi ≈ 3 − 4) density fluctuations at the top of the pedestal. A novel diagnostic technique combining DBS with crosspolarization scattering (CP-DBS) enab...
متن کاملGyrokinetic microtearing turbulence.
The nonlinear dynamics of microtearing modes in standard tokamak plasmas are investigated by means of ab initio gyrokinetic simulations. The saturation levels of the magnetic field fluctuations can be understood in the framework of a balance between (small poloidal wave number) linear drive and small-scale dissipation. The resulting heat transport is dominated by the electron magnetic component...
متن کامل