Modelling of Profile Control with Lower Hybrid Wave Injection in the HL-2A Single-Null Divertor Plasma

Abstract

Separatrix of the single-null diverted plasma produced in the HL-2A tokamak is determined by a fast algorithm for identifying plasma boundary. Higher power LH wave (1.5MW) is injected into the diverted plasma with a slightly asymmetric spectrum. Plasma heating by electron Landau interaction results in operation scenarios of preferentially dominant electron heating. Current profile control under the dominant electron heating condition is investigated with numerical simulation. Due to the off-axis driven current, an RS q-profile is formed, and an enhanced confinement regime with steep electron temperature gradient is produced. The clear decrease of the electron thermal conductivity in the vicinity of the shear reversal shows that an electron-ITB is developed. When higher LH power injects into the target plasma that is heated by neutral beam injection, the ion temperature has a large increment in addition to the high increase of electron temperature. The temperature profiles indicate that an enhanced core confinement is established with both ion-ITB and electron-ITB developed.

Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

“…24 The T e barriers can be obtained in discharges with predominantly electron heating (e.g., results presented in Refs. [25][26][27][28].…”