Recent experiments in the EAST and HT-7 superconducting tokamaks

Abstract

First diverter plasma configuration in EAST was obtained in the second campaign after the last IAEA meeting. To support the long pulse diverted plasma discharges, new capabilities including the fully actively water cooled in-vessel components, current drive and heating power, diagnostics, real-time plasma control algorithm were developed. Pre-program shape and RZIP feedback control produce a variety of shaped plasma, which cover almost designed configuration. RTEFIT/ISOFLUX control algorithm was primarily realized. A number of operational issues, such as plasma initiation, ramp up and configuration control with constraints of superconducting coils were successfully investigated. The physical engineering capability on the superconducting magnetic system of EAST was assessed by simulating discharges. Since the last IAEA meeting, experiments in HT-7 focused on long pulse discharges under different scenarios and high power heating to support EAST experiments both physically and technically. The long pulse discharges up to 400s renews the records in HT-7. The high performance regimes have been greatly extended. The investigation of sawtooth activities in ohmic and LHCD plasmas of HT-7 by 2D ECE image and high resolution soft-X arrays support the turbulence model instead of the fast reconnection of the m=1 magnetic island. Coexistence of electron mode and ion mode in high density ohmic plasma has been observed by 2D ECEI in HT-7. The spectral characteristics of GAM and the nonlinear three wave coupling at the GAM frequency has been investigated.

Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

“…EAST is a fully superconducting tokamak device with RF dominant heating [22], primarily tasked with demonstrating high performance long pulse discharges in support of ITER and the conceptual China Fusion Engineering Test Reactor (CFETR) [23]. To support this mission, the EAST upper divertor was upgraded to an ITER-like Tungsten mono-block structure capable of exhausting 10 MW/m 2 .…”

Theoretical relation between halo current-plasma energy displacement/deformation in EAST

“…The number of research articles has been published to investigate the halo current in other Tokamak devices such as JET [3], JT-60U [4], and NSTX [5]. Like in Experimental Advanced Superconducting Tokamak (EAST) reactor [6][7][8], there are some failures of the feedback control in VD event caused by disruption. The EAST reactor is designed by Institute of Plasma Physics, Chinese Academy of Sciences, P.R.…”

Applications of Visible Imaging Diagnostics on EAST Tokamak

“…EAST is a superconducting tokamak with modern divertor configuration [7,8]. The design parameters of EAST include: a major radius of 1.7 m, a minor radius of 0.4 m, a plasma current of 1 MA, a toroidal field of 3.5 T, and a pulse length of 1000 s.…”