Modification of H-mode pedestal structure with lower hybrid waves on Alcator C-Mod

Modification of H-mode pedestal structure with lower hybrid waves on Alcator C Mod

The application of lower hybrid waves (LH) in H-mode plasmas on Alcator C-Mod can result in significant reduction of core particle inventory, with no significant degradation of energy confinement. This phenomenon has been observed in steady enhanced Dα (EDA) H-mode targets, which are sustained by ion cyclotron RF auxiliary heating, in which pedestal density nped is usually tied firmly to plasma...

H-mode Pedestal Studies in Alcator C-mod

H-Mode Pedestal and Threshold Studies Over an Expanded Operating Space on Alcator C-Mod

This paper reports on studies of the edge transport barrier and transition threshold of the High Confinement (H) mode of operation on the Alcator C-Mod tokamak [I. H. Hutchinson et al, Phys. Plasmas 1, 1511 (1994)], over a wide range of toroidal field (2.6-7.86 T) and plasma current (0.4-1.7 MA). The H-mode power threshold and edge temperature at the transition increase with field. Barrier widt...

H Mode Confinement in Alcator C-mod

A series of experiments, examining the confinement properties of ion cyclotron range of frequencies (ICRF) heated H mode plasmas, has been carried out on the Alcator C-Mod tokamak. Alcator C-Mod is a compact tokamak that operates at high particle, power and current densities at toroidal fields up to 8 T. Under these conditions the plasma is essentially thermal with very little contribution to t...

H-mode Pedestal Characteristics and Mhd Stability of the Edge Plasma in Alcator C-mod

Under most operational conditions of Alcator C-Mod the dominant type of H-mode is the steady state enhanced Dα mode (EDA), characterized by good energy confinement, continuously degraded impurity confinement and absence of regular ELMs. In this regime a quasicoherent (QC) electromagnetic mode (kθ~5 cm, f~100 kHz) is observed, localized in the region of the density pedestal. Experimental evidenc...