Lower hybrid current drive and ion cyclotron range of frequencies heating experiments in H-mode plasmas in Experimental Advanced Superconducting Tokomak

Abstract

An ion cyclotron range of frequencies (ICRF) system with power up to 6.0 MW and a lower hybrid current drive (LHCD) system up to 4 MW have been applied for heating and current drive experiments in Experimental Advanced Superconducting Tokomak (EAST). Significant progress has been made with ICRF heating and LHCD for realizing the H-mode plasma operation in EAST. During 2010 and 2012 experimental campaigns, ICRF heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H minority heating (H-MH) mode. The H-MH mode produced good plasma performance, and realized H-mode using ICRF power alone in 2012. In 2010, H-modes were generated and sustained by LHCD alone, where lithium coating and gas puffing near the mouth of the LH launcher were applied to improve the LHCD power coupling and penetration into the core plasmas of H-modes. In 2012, the combination of LHCD and ICRH power extended the H-mode duration up to over 30 s. H-modes with various types of edge localized modes (ELMs) have been achieved with HIPB98(y, 2) ranging from 0.7 to over unity. A brief overview of LHCD and ICRF Heating experiment and their application in achieving H-mode operation during these two campaigns will be presented.

Estimation of the sheath power dissipation induced by ion cyclotron resonance heating

“…In this section, the hydrodynamic equations (2)-( 5) and the current balance equations (10)-( 13) are solved numerically with boundary condition equations (6)-( 9), and the sheath power dissipation is then obtained. Besides the energetic ion, + H , and background ion, + D , the two common impurity light ions in EAST such as lithium ions + Li ( = Z 1) and carbon ions The energetic ion enters the sheath with the energy of hundreds of eV,   T 100 eV 1 500 eV, and the concentration is below 10% [25], i.e.,   N 0 0.1.…”

Results of ICRF Heating Experiments from the EAST 2010 Campaign

“…A typical case with lower concentration is shown in Fig. 6, where an overview of discharge with a hydrogen concentration of about 7% is shown [9] . The parameters are as follows: plasma current I p = 500 kA, toroidal magnetic field B 0 ∼ 2.0 T and hydrogen concentration was decreased up to 7%.…”